Chinese Premier Li Qiang said Sunday that BRICS countries should strive to become the vanguard in advancing the reform of global governance.
Li made the remarks when addressing the plenary session of "Peace and Security and Reform of Global Governance" of the 17th BRICS Summit, calling on the bloc to safeguard world peace and tranquility, and promote the peaceful settlement of disputes.
Leaders of BRICS countries attended the meeting, which was presided by Brazilian President Luiz Inacio Lula da Silva.
Li said at present, changes unseen in a century are unfolding at an accelerated pace, international rules and order are being severely challenged, and the authority and efficacy of multilateral institutions continue to wane.
The vision of global governance put forward by Chinese President Xi Jinping, characterized by extensive consultation, joint contribution and shared benefits, has been further demonstrating its contemporary value and practical significance, Li said.
In face of growing conflicts and differences, it is needed to enhance extensive consultation based on equality and mutual respect; In face of deeply intertwined common interests, it is needed to pursue joint contribution through solidarity; In face of mutually beneficial development opportunities, it is needed to hold an open mind to seek mutual success and shared benefits, said Li.
As the leading force of the Global South, BRICS countries should uphold independence and self-reliance, demonstrate a sense of responsibility, and play a greater role in building consensus and synergies, Li noted.
The Chinese premier called on the group to hold fast to morality and justice, and seek fundamental solutions based on the merits of each issue.
BRICS countries should also focus on development and bolster the drivers of economic growth, said Li, adding that they should actively spearhead development cooperation and tap into the growth potential of emerging sectors.
Noting that China will establish a China-BRICS research center on new quality productive forces this year, Li also announced a scholarship established for BRICS countries to facilitate talent cultivation in sectors including industry and telecommunication.
It is essential for BRICS countries to foster inclusiveness and advance exchanges and mutual learning among civilizations, Li said, calling on the countries to act as advocates for the harmonious coexistence of civilizations, striving to ensure diverse civilizations flourish together through mutual reinforcement.
China stands ready to join hands with other BRICS countries to promote global governance in a more just, equitable, efficient and orderly direction, working collectively to build a better world, he said.
The leaders of countries participating in the meeting noted that the BRICS cooperation mechanism has continued to grow stronger and more representative, with its international influence rising steadily.
It has provided an important platform for Global South countries to defend their right to development, uphold international fairness and justice, and participate in the reform of the global governance system, they said.
In an increasingly turbulent world where unilateralism and protectionism are on the rise, they said, BRICS countries should enhance solidarity and coordination, defend the purposes and principles of the UN Charter, uphold and practice multilateralism, and make greater contribution to promoting common development, improving global governance, and fostering lasting peace and prosperity in the world.
The meeting adopted the Rio de Janeiro Declaration of the 17th BRICS Summit.
Chinese Premier Li Qiang on Monday called for commitment to building an open world economy, and urged the importance of opposing unilateralism and protectionism.
In his remarks addressing the plenary sessions of the 17th BRICS Summit, Li also stressed the need to maintain the stability and smoothness of industrial and supply chains.
Facing an intertwined international situation, China and Europe should enhance communication, understanding, and mutual trust to become "anchors of stability" for the world and be reliable and strong partners that achieve mutual success, Chinese Foreign Minister Wang Yi said during a meeting with Belgium's Prime Minister Bart de Wever in Brussels on Monday.
Wang, also a member of the Political Bureau of the CPC Central Committee, is visiting Europe from June 30 to July 6, at the invitation of High Representative for Foreign Affairs and Security Policy of the EU Kaja Kallas, Federal Foreign Minister of Germany Johann Wadephul, and Minister for Europe and Foreign Affairs of France Jean-Noël Barrot.
Wang said that Belgium is a founding member of the European Union and the location of its headquarters, playing a unique role in the process of European integration and in relations between China and Europe. China appreciates the new Belgian government's rational and pragmatic policy toward China and is willing to promote the traditional friendship with Belgium and to push the all-round partnership of friendship and cooperation between the two countries to continue moving forward steadily.
Insisting on high-quality development and a high level of opening up, China welcomes more Belgian enterprises to develop in the country and hopes that Belgium will also provide a fair, safe, and predictable business environment for Chinese companies investing in Belgium, Wang noted.
Wang noted that 2025 marks the 50th anniversary of the establishment of diplomatic relations between China and Europe, which is of significant importance for carrying forward the past and ushering in the future. "The half-century of exchanges between China and Europe fully proves that both sides can fully respect each other and achieve win-win cooperation," Wang said.
Wang emphasized that facing today's intertwined international situation, China and Europe, as two major global forces, markets, and civilizations, should strengthen communication, enhancing understanding, and consolidating mutual trust to jointly uphold multilateralism and the free trade system. China and Europe should be "anchors of stability" for the world and be reliable and strong partners that achieve mutual success.
De Wever said that Belgium and China have a long history of exchanges with active local friendly exchanges, which played a gateway role in Europe-China cooperation. He said that having visited China several times, he has been deeply impressed by China's development achievements. Although Europe and China have different perspectives, in the face of the current complex geopolitical situation, both sides should strengthen exchanges and enhance mutual trust, De Wever said.
De Wever said that Belgium firmly believes in multilateralism, supports Europe in strengthening its autonomy, and looks forward to positive outcomes from the meeting of European and Chinese leaders. He emphasized that the Belgian government firmly adheres to the one China policy and will not change this stance.
The two sides also exchanged views concerning the situation in Ukraine.
Premier of the State Council Li Qiang will attend the 17th BRICS Summit upon invitation in Rio de Janeiro, Brazil from July 5 to 8, Chinese Foreign Ministry spokesperson Mao Ning announced at a regular press conference on Wednesday.
When asked about China's expectations for the BRICS Summit, Mao said the BRICS cooperation mechanism offers the most important platform for the solidarity and cooperation among emerging markets and developing countries in the world. It's an important force for realizing an equal and orderly multipolar world and a universally beneficial and inclusive economic globalization.
Mao noted that this will be the first summit after the new member Indonesia, and 10 partner countries joined BRICS. Multiple emerging markets, developing countries, and international and regional organizations are invited to the summit.
China looks forward to working with all parties to consolidate the BRICS strategic partnership, make due contributions to safeguarding multilateralism, promoting common development and improving global governance, and advance the high-quality development of greater BRICS cooperation, Mao added.
Initially comprised of Brazil, Russia, India, China, and South Africa, the recently expanded BRICS now also includes Egypt, Ethiopia, Indonesia, Iran, Saudi Arabia, and the United Arab Emirates, according to the official BRICS 2025 website. The grouping has evolved into a platform for South-South cooperation and political coordination.
Based on the Johannesburg Declaration, the 2024 Kazan Summit approved the creation of a BRICS partner country category, which now includes Belarus, Bolivia, Cuba, Kazakhstan, Malaysia, Nigeria, Thailand, Uganda, Uzbekistan, and most recently, Vietnam.
Experts noted that the expanded format reflects BRICS' rising capacity to represent the Global South. This year's meeting is expected to offer broader representation and a stronger voice for developing nations amid challenges to multilateralism and international cooperation, they added.
"This summit marks the first full gathering of the '11 members+10 partners' BRICS family. Within this new system, developing countries will no longer be the silent majority but a vital force in global governance," Wang Youming, Director of the Institute of Developing Countries at the China Institute of International Studies, told the Global Times on Wednesday.
Growing voice
The inclusion of Indonesia as a full member and Vietnam as a partner country further strengthens BRICS' representativeness and influence. The enlarged grouping spans Asia, Africa, Latin America, and the Middle East, representing nearly half of the global population and about 30 percent of global GDP, contributing over 50 percent of global economic growth, according to an article published on People's Daily Wednesday.
''Joining BRICS cooperation is good for Vietnam's development and the common interest of BRICS countries and the Global South. Having a new partner country in the BRICS family symbolizes the BRICS' growing representativeness, appeal and impact,'' Chinese Foreign Ministry spokesperson Guo Jiakun said on June 16.
China stands ready to work with other BRICS members and partner countries for a closer and more all-round, result-oriented and inclusive partnership, advance high-quality greater BRICS cooperation, and contribute more to defending multilateralism and global fairness and justice and advocating common development, Guo added.
Ali El-Hefny, Vice President of the Egypt-China Friendship Association and former Egyptian Deputy Foreign Minister, noted BRICS' increasing influence and its critical role in promoting South-South cooperation and common development, the People's Daily reported.
Against a backdrop of frequent geopolitical conflicts and disruptions to the international trade order, BRICS' role in articulating the voice of developing nations has never been more critical, Wang said.
"From the perspectives of economic scale, population, and political representation, BRICS surpasses regional groupings like the G7. It is therefore vital for BRICS to speak with one voice in confronting trade protectionism, geopolitical tensions, and climate change," Wang added.
On June 24, BRICS issued a Joint Statement on the Escalation of the Security Situation in the Middle East Following the Military Strikes on the Territory of the Islamic Republic of Iran, calling on all parties to use existing channels of dialogue and diplomacy, with a view to de-escalate the situation and resolving their differences through peaceful means, which according to experts, demonstrates BRICS' unified voice on global peace and governance.
Emerging challenges
The 2025 summit is also expected to address key global issues, including the governance of artificial intelligence (AI). According to the BRICS official website, the bloc seeks to improve the legitimacy, equity in participation, and efficiency of global institutions such as the UN, IMF, World Bank, and WTO, while bolstering sustainable social and economic development and promote social inclusion, said the BRICS website.
Brazil, as the current BRICS Chair, has outlined two strategic priorities: Global South Cooperation and BRICS Partnerships for Social, Economic, and Environmental Development. According to the International Institute for Sustainable Development, Brazil's agenda includes six key areas: global health, trade and finance, climate change, AI governance, peace and security, and institutional development.
Chen Fengying, a research fellow at the China Institutes of Contemporary International Relations, told the Global Times on Wednesday that green development, green finance, and AI will be key areas of discussion during the summit.
"On the future of emerging industries, the Global South will establish its own rules and voice. BRICS will play a pivotal role, with China, as a leading player in these sectors, expected to take the lead," Chen said.
In response to a media enquiry regarding whether China agrees to become a signatory to the Southeast Asia Nuclear Weapon-Free Zone Treaty (SEANWFZ) along with Russia, and if so, why China has made this decision now, Chinese Foreign Ministry spokesperson Mao Ning said on Thursday that as ASEAN's comprehensive strategic partner and friendly neighbor, China has always firmly supported the establishment of a Southeast Asia Nuclear Weapon-Free Zone.
China and Russia have agreed to become signatories to the SEANWFZ, while the US is currently reviewing the treaty before signing, said Malaysian Foreign Minister Mohamad Hasan, as reported by Malaysian National News Agency Bernama.
Mohamad said the involvement of superpowers in the treaty would help preserve Southeast Asia as a region of peace, free of nuclear weapons, per Bernama.
"We have repeatedly made it clear that we are willing to be the first to sign the treaty. China is willing to continue communicating with ASEAN members regarding the signing of the protocol," Mao said.
In response to some Australian media outlets recently hyping China-related remarks made by Fiji's Prime Minister Sitiveni Rabuka while he was answering reporters' questions at the National Press Club of Australia, the Chinese Embassy in Fiji said in a statement on Thursday that the claims about "China setting up a military base in the Pacific" are false narratives. They are baseless and driven by ulterior motives.
Some media outlet, including Australian Broadcasting Corporation (ABC), has highlighted Fiji's Prime Minister Sitiveni Rabuka's remarks on "not welcome" any Chinese military bases in the region in the headline. While in the news, ABC also noted that Rabuka told the Press Club that he didn't believe China was actively looking for a military base in Pacific.
The Embassy noticed that Prime Minister Rabuka said he did not believe that China needs a base in the Pacific. The claims about "China setting up a military base in the Pacific" are false narratives. They are baseless and driven by ulterior motives, said the spokesperson.
China's presence in the Pacific is focused on building roads and bridges to improve people's livelihoods, not on stationing troops or setting up military bases. Never has China stirred up any dispute in the Pacific Region, violated any inch of land from Pacific Island Countries, or signed any agreement that forced Pacific Island Countries to sacrifice their sovereignty, according to the spokesperson.
China remains firmly committed to the international nuclear non-proliferation regime with the Treaty on the Non-Proliferation of Nuclear Weapons as the cornerstone and to the Pacific Nuclear Free Zone Treaty. We firmly support Pacific Island Countries in playing a bigger role in regional and international affairs, and will maintain communication with Pacific Island Countries on major international and regional hotspot issues to make positive contributions to the peace and stability of the Pacific region, said the Embassy spokesperson.
China and Fiji are comprehensive strategic partners, and security cooperation is part of our bilateral relations. China applauds Prime Minister Rabuka's vision for the Pacific as an "Ocean of Peace", and is committed to work with Fiji in contributing to peace and security in the region and beyond, said the Embassy spokesperson.
The spokesperson of the Embassy emphasizes that the Pacific Ocean is large enough to accommodate win-win cooperation among all countries. China sincerely calls on relevant parties to avoid viewing China-Fiji and China-Pacific Island Countries relations through the narrow lens of geopolitical games, hyping up the so-called threats of geopolitical competition in the region, forcing Pacific Island Countries to "take sides", and imposing their own interests on these countries. Instead, we urge them to do more concrete things that contribute to the development of Pacific Island Countries and the well-being of the people.
Over the past 20 years, the pace of equal and mutually beneficial bilateral cooperation between China and Pacific island countries has accelerated, which has caused unease and dissatisfaction among Western countries. They are attempting to use such propaganda tactic to drive a wedge between Pacific island nations and China — a common tactic of diplomatic blackmail they employ, Yu Lei, a professor from the Department of International Politics and Economics at Shandong University, told the Global Times.
China has always developed its relations with island countries based on the principles of peaceful coexistence and equality and mutual benefit, and has no intention of escalating military tensions in the region, said Yu.
In the statement, the spokesperson also said that the Embassy noticed Prime Minister Rabuka commented that China stood with Fiji when Australia turned away. He remarked that Fiji and China respect each other's sovereignty and we have not had any intrusion into our sovereign space.
China has no interest in geopolitical competition, or seeking the so-called "sphere of influence." There is no political strings attached to China's assistance, no imposing one's will onto others, and no empty promises. China advocates for all countries to uphold Pacific Island Countries' autonomy in making decisions, putting development first, and staying open and inclusive when developing relations with Pacific Island Countries, said the spokesperson.
China always believes that the Pacific is the homeland of the people of Pacific Island Countries, not the backyard of big powers outside the region. The Pacific is a stage for cooperation, not a battlefield for vicious competition. It makes no sense to view China's sincere help to Pacific Island Countries from the narrow perspective of geo-competition, said the spokesperson.
Forcing Pacific Island Countries to "choose sides" can never address the urgent demands for development of the people from the Pacific Island Countries, nor the common threat of climate change to mankind, said the spokesperson.
At nearly 30 hours and 20,000 kilometers away from Beijing, Buenos Aires in Argentina is one of the furthest destinations in the world from the Chinese capital. In a popular 2024 stand-up comedy show, Yan Hexiang, a Chinese actor and crosstalk performer, humorously pointed out that the antipodal point to Beijing is located in the Pampas grasslands of Argentina. However, the distance between Argentina and China doesn't seem so far. Just about 38 kilometers from Ministro Pistarini International Airport in Buenos Aires, is a largely commercial section about five blocks long in the district of Belgrano, where a towering Chinese-style archway greets you, inscribed with the words "China Town."
The Global Times has visited many "Chinatowns" around the world, including those in Washington, London, and Nagasaki. However, Buenos Aires' "Chinatown" is quite different from the rest. This is immediately apparent upon entry: On a Sunday evening, the streets bustle with activity, restaurants have long wait times, and shops attend to numerous customers. Upon closer inspection, the Global Times noticed that non-Chinese diners and shoppers actually outnumber Chinese ones.
In Chinese, the word "foreigner" is used to refer to anyone who is not Chinese, therefore within the context of Buenos Aires, it is used to refer to non-Chinese locals. In many other "Chinatowns" in the world, Chinese nationals are surrounded by their own, and while the occasional less-than-authentic Chinese cuisine might remind them that "this is not China," the presence of Chinese nationals gives a sense of belonging. In contrast, in Buenos Aires' "Chinatown," surrounded by countless local faces, the "Chinese nationals" seem more like visitors passing through.
Famous Chinese hotpot restaurant brands like Little Sheep Mongolian Hot Pot, Shoo Loong Kan Hot Pot, and Haidilao Hot Pot, commonly found in American "Chinatowns," are conspicuously absent. However, Chinese culture, cuisine, and products are everywhere, and even bubble tea has become a favorite among the youth in the "Chinatown." A capybara in a shop window observes the comings and goings, much like its counterpart in the trendy toy area of Chaoyang district's Joy City mall in Beijing, 20,000 kilometers away. In addition to Chinese elements, graffiti in the style of Japanese animator, filmmaker, and manga artist Hayao Miyazaki features the Chinese characters for "Visited Here," and posters of South Korean idols appear in shop windows, indicating that this "Chinatown" not only spreads Chinese culture but also incorporates East Asian elements. A few steps further, a street magician interacts with the audience, with a prominent image of "Guanyin" on the wall behind him, as if everything before us is being witnessed by the bodhisattva. Why are there so many "foreigners" in Buenos Aires' "Chinatown"? Locals provided various answers. Most people's first response was that "Chinatown" is an important social media hotspot in Buenos Aires. If you plan a day trip to the city, this is a must-visit location. "You visited on the last day of a long weekend, so of course, there were many people shopping and dining; people love going to Chinatown," a local Chinese national told the Global Times.
Another local explained that unlike many other "Chinatowns," Buenos Aires' "Chinatown" has a significant number of Chinese residents, but it is not the main gathering place for the local Chinese community. With its trendy atmosphere, it naturally attracts a lot of young people, making the "foreigners" seem particularly popular.
What is it that attracts so many "foreigners" to this "Chinatown"? "Chinese cuisine" topped the list of mentions, with Chinese products and culture also frequently cited among those interviewed by the Global Times. "Yufu" is a relatively authentic Cantonese restaurant in Buenos Aires' "Chinatown," where Chinese food is on the pricier side compared to local dining options. Yet even at 2:10 pm on Sunday, the restaurant was still packed, and the number of Chinese diners was visibly less than half of all patrons.
"Exquisite, compact, and easy to explore," said Nora, director of a research company in Buenos Aires, when asked about the "Chinatown". She added, "I love the dim sum in 'Chinatown'; I enjoy the exotic atmosphere there. The shop owners are very friendly, and the products are diverse; you can find many things you want in one store."
Liu Jialong, a 19-year-old local of Chinese descent, told the Global Times that "Buenos Aires also has a 'Koreantown,' which is only one street and much smaller than 'Chinatown.' It used to be very popular, but its popularity has declined. In contrast, 'Chinatown' is booming now."
If China were not becoming stronger and developing so rapidly, would people be increasingly interested in China? he asked.
On the diplomatic front, the Milei administration made some comments about China that were deemed newsworthy by some Western media outlets before taking office. However, Argentines, including scholars and businesspeople, that the Global Times reporter met here during the trip place great importance on China-Argentina relations. China is Latin America's second-largest trading partner and holds the top position in several countries. In a recent survey released by the Global Times Institute (GTI), in collaboration with the Latin American Council of Social Sciences (CLACSO) and the China-Latin America Education and Culture Center, on the "China-LAC mutual perception" conducted in both regions found that the most prominent impression left by China on Latin Americans was "technology." When asked to fill in keywords that represent their primary impressions of China, a Gen Z respondent from Argentina mentioned "DeepSeek." Of all those interviewed by the Global Times, Wu Ditai, a young Argentine scholar who studied at Peking University, was the most knowledgeable about China. Watching him mimic the distinct drawl common among Beijing's taxi drivers was as impressive as it was comedic.
"It's not just 'Chinatown'; if you look deeper, Argentines are very curious about China. They want to know why China is developing so quickly and what experiences Argentina can learn from," Wu Ditai said. He has plans to return to China soon and hopes to travel across all provinces to gain a deeper understanding of the country.
Of course, the reality is that many Argentines do not have a sufficient understanding of China. Most of their information comes from the media, especially Western media sources and social media.
An Argentine journalist told the Global Times that while there is considerable coverage of China in local media, the current lack of understanding among Argentines about China is unlikely to change in the short term.
"'China Travel' is a trending topic now, and Argentina has visa-free access. The real China is right there, and everyone is welcomed to learn about it," the Global Times told Wu Ditai.
Researchers have finally deciphered a complete human genetic instruction book from cover to cover.
The completion of the human genome has been announced a couple of times in the past, but those were actually incomplete drafts. “We really mean it this time,” says Evan Eichler, a human geneticist and Howard Hughes Medical Institute investigator at the University of Washington in Seattle.
The completed genome is presented in a series of papers published online March 31 in Science and Nature Methods.
An international team of researchers, including Eichler, used new DNA sequencing technology to untangle repetitive stretches of DNA that were redacted from an earlier version of the genome, widely used as a reference for guiding biomedical research.
Deciphering those tricky stretches adds about 200 million DNA bases, about 8 percent of the genome, to the instruction book, researchers report in Science. That’s essentially an entire chapter. And it’s a juicy one, containing the first-ever looks at the short arms of some chromosomes, long-lost genes and important parts of chromosomes called centromeres — where machinery responsible for divvying up DNA grips the chromosome.
“Some of the regions that were missing actually turn out to be the most interesting,” says Rajiv McCoy, a human geneticist at Johns Hopkins University, who was part of the team known as the Telomere-to-Telomere (T2T) Consortium assembling the complete genome. “It’s exciting because we get to take the first look inside these regions and see what we can find.” Telomeres are repetitive stretches of DNA found at the ends of chromosomes. Like aglets on shoelaces, they may help keep chromosomes from unraveling.
Data from the effort are already available for other researchers to explore. And some, like geneticist Ting Wang of Washington University School of Medicine in St. Louis, have already delved in. “Having a complete genome reference definitely improves biomedical studies.… It’s an extremely useful resource,” he says. “There’s no question that this is an important achievement.”
But, Wang says, “the human genome isn’t quite complete yet.”
To understand why and what this new volume of the human genetic encyclopedia tells us, here’s a closer look at the milestone. What did the researchers do? Eichler is careful to point out that “this is the completion of a human genome. There is no such thing as the human genome.” Any two people will have large portions of their genomes that range from very similar to virtually identical and “smaller portions that are wildly different.” A reference genome can help researchers see where people differ, which can point to genes that may be involved in diseases. Having a view of the entire genome, with no gaps or hidden DNA, may give scientists a better understanding of human health, disease and evolution.
The newly complete genome doesn’t have gaps like the previous human reference genome. But it still has limitations, Wang says. The old reference genome is a conglomerate of more than 60 people’s DNA (SN: 3/4/21). “Not a single individual, or single cell on this planet, has that genome.” That goes for the new, complete genome, too. “It’s a quote-unquote fake genome,” says Wang, who was not involved with the project.
The new genome doesn’t come from a person either. It’s the genome of a complete hydatidiform mole, a sort of tumor that arises when a sperm fertilizes an empty egg and the father’s chromosomes are duplicated. The researchers chose to decipher the complete genome from a cell line called CHM13 made from one of these unusual tumors.
That decision was made for a technical reason, says geneticist Karen Miga of the University of California, Santa Cruz. Usually, people get one set of chromosomes from their mother and another set from their father. So “we all have two genomes in every cell.”
If putting together a genome is like assembling a puzzle, “you essentially have two puzzles in the same box that look very similar to each other,” says Miga, borrowing an analogy from a colleague. Researchers would have to sort the two puzzles before piecing them together. “Genomes from hydatidiform moles don’t present that same challenge. It’s just one puzzle in the box.”
The researchers did have to add the Y chromosome from another person, because the sperm that created the hydatidiform mole carried an X chromosome.
Even putting one puzzle together is a Herculean task. But new technologies that allow researchers to put DNA bases — represented by the letters A, T, C and G — in order, can spit out stretches up to more than 100,000 bases long. Just as children’s puzzles are easier to solve because of larger and fewer pieces, these “long reads” made assembling the bits of the genome easier, especially in repetitive parts where just a few bases might distinguish one copy from another. The bigger pieces also allowed researchers to correct some mistakes in the old reference genome.
What did they find? For starters, the newly deciphered DNA contains the short arms of chromosomes 13, 14, 15, 21 and 22. These “acrocentric chromosomes” don’t resemble nice, neat X’s the way the rest of the chromosomes do. Instead, they have a set of long arms and one of nubby short arms.
The length of the short arms belies their importance. These arms are home to rDNA genes, which encode rRNAs, which are key components of complex molecular machines called ribosomes. Ribosomes read genetic instructions and build all the proteins needed to make cells and bodies work. There are hundreds of copies of these rDNA regions in every person’s genome, an average of 315, but some people have more and some fewer. They’re important for making sure cells have protein-building factories at the ready.
“We didn’t know what to expect in these regions,” Miga says. “We found that every acrocentric chromosome, and every rDNA on that acrocentric chromosome, had variants, changes to the repeat unit that was private to that particular chromosome.”
By using fluorescent tags, Eichler and colleagues discovered that repetitive DNA next to the rDNA regions — and perhaps the rDNA too — sometimes switches places to land on another chromosome, the team reports in Science. “It’s like musical chairs,” he says. Why and how that happens is still a mystery.
The complete genome also contains 3,604 genes, including 140 that encode proteins, that weren’t present in the old, incomplete genome. Many of those genes are slightly different copies of previously known genes, including some that have been implicated in brain evolution and development, autism, immune responses, cancer and cardiovascular disease. Having a map of where all these genes lie may lead to a better understanding of what they do, and perhaps even of what makes humans human.
One of the biggest finds may be the structure of all of the human centromeres. Centromeres, the pinched portions which give most chromosomes their characteristic X shape, are the assembly points for kinetochores, the cellular machinery that divvies up DNA during cell division. That’s one of the most important jobs in a cell. When it goes wrong, birth defects, cancer or death can result. Researchers had already deciphered the centromeres of fruit flies and the human 8, X and Y chromosomes (SN: 5/17/19), but this is the first time that researchers got a glimpse of the rest of the human centromeres.
The structures are mostly head-to-tail repeats of about 171 base pairs of DNA known as alpha satellites. But those repeats are nestled within other repeats, creating complex patterns that distinguish each chromosome’s individual centromere, Miga and colleagues describe in Science. Knowing the structures will help researchers learn more about how chromosomes are divvied up and what sometimes throws off the process. Researchers also now have a more complete map of epigenetic marks — chemical tags on DNA or associated proteins that may change how genes are regulated. One type of epigenetic mark, known as DNA methylation, is fairly abundant across the centromeres, except for one spot in each chromosome called the centromeric dip region, Winston Timp, a biomedical engineer at Johns Hopkins University and colleagues report in Science.
Those dips are where kinetochores grab the DNA, the researchers discovered. But it’s not yet clear whether the dip in methylation causes the cellular machinery to assemble in that spot or if assembly of the machinery leads to lower levels of methylation.
Examining DNA methylation patterns in multiple people’s DNA and comparing them with the new reference revealed that the dips occur at different spots in each person’s centromeres, though the consequences of that aren’t known.
About half of genes implicated in the evolution of humans’ large, wrinkly brains are found in multiple copies in the newly uncovered repetitive parts of the genome (SN: 2/26/15). Overlaying the epigenetic maps on the reference allowed researchers to figure out which of many copies of those genes were turned on and off, says Ariel Gershman, a geneticist at Johns Hopkins University School of Medicine.
“That gives us a little bit more insight into which of them are actually important and playing a functional role in the development of the human brain,” Gershman says. “That was exciting for us, because there’s never been a reference that was accurate enough in these [repetitive] regions to tell which gene was which, and which ones are turned on or off.”
What is next? One criticism of genetics research is that it has relied too heavily on DNA from people of European descent. CHM13 also has European heritage. But researchers have used the new reference to discover new patterns of genetic diversity. Using DNA data collected from thousands of people of diverse backgrounds who participated in earlier research projects compared with the T2T reference, researchers more easily and accurately found places where people differ, McCoy and colleagues report in Science.
The Telomere-to-Telomere Consortium has now teamed up with Wang and his colleagues to make complete genomes of 350 people from diverse backgrounds (SN: 2/22/21). That effort, known as the pangenome project, is poised to reveal some of its first findings later this year, Wang says.
McCoy and Timp say that it may take some time, but eventually, researchers may switch from using the old reference genome to the more complete and accurate T2T reference. “It’s like upgrading to a new version of software,” Timp says. “Not everyone is going to want to do it right away.”
The completed human genome will also be useful for researchers studying other organisms, says Amanda Larracuente, an evolutionary geneticist at the University of Rochester in New York who was not involved in the project. “What I’m excited about is the techniques and tools this team has developed, and being able to apply those to study other species.”
Eichler and others already have plans to make complete genomes of chimpanzees, bonobos and other great apes to learn more about how humans evolved differently than apes did. “No one should see this as the end,” Eichler says, “but a transformation, not only for genomic research but for clinical medicine, though that will take years to achieve.”
With soils rich for cultivation, most land in the Midwestern United States has been converted from tallgrass prairie to agricultural fields. Less than 0.1 percent of the original prairie remains.
This shift over the last 160 years has resulted in staggering — and unsustainable — soil erosion rates for the region, researchers report in the March Earth’s Future. The erosion is estimated to be double the rate that the U.S. Department of Agriculture says is sustainable. If it continues unabated, it could significantly limit future crop production, the scientists say.
In the new study, the team focused on erosional escarpments — tiny cliffs formed through erosion — lying at boundaries between prairie and agricultural fields (SN: 1/20/96). “These rare prairie remnants that are scattered across the Midwest are sort of a preservation of the pre-European-American settlement land surface,” says Isaac Larsen, a geologist at the University of Massachusetts Amherst.
At 20 sites in nine Midwestern states, with most sites located in Iowa, Larsen and colleagues used a specialized GPS system to survey the altitude of the prairie and farm fields. That GPS system “tells you where you are within about a centimeter on Earth’s surface,” Larsen says. This enables the researchers to detect even small differences between the height of the prairie and the farmland.
At each site, the researchers took these measurements at 10 or more spots. The team then measured erosion by comparing the elevation differences of the farmed and prairie land. The researchers found that the agricultural fields were 0.37 meters below the prairie areas, on average. This corresponds to the loss of roughly 1.9 millimeters of soil per year from agricultural fields since the estimated start of traditional farming at these sites more than a century and a half ago, the researchers calculate. That rate is nearly double the maximum of one millimeter per year that the USDA considers sustainable for these locations.
There are two main ways that the USDA currently estimates the erosion rate in the region. One way estimates the rate to be about one-third of that reported by the researchers. The other estimates the rate to be just one-eighth of the researchers’ rate. Those USDA estimates do not include tillage, a conventional farming process in which machinery is used to turn the soil and prepare it for planting. By disrupting the soil structure, tilling increases surface runoff and erosion due to soil moving downslope.
Larsen and colleagues say that they would like to see tillage incorporated into the USDA’s erosion estimates. Then, the USDA numbers might better align with the whopping 57.6 billion metric tons of soil that the researchers estimate has been lost across the entire region in the last 160 years.
This massive “soil loss is already causing food production to decline,” Larsen says. As soil thickness decreases, the amount of corn successfully grown in Iowa is reduced, research shows. And disruption to the food supply could continue or worsen if the estimated rate of erosion persists.
Not everyone is convinced that the average amount of soil lost each year has remained steady since farming in the region started. Much of the erosion that the researchers measured could have been caused in the earlier histories of these sites, dating back to when farmers “began to break prairies and/or forests and clear things,” says agronomist Michael Kucera.
Perhaps current erosion rates have slowed, says Kucera, who is the steward of the National Erosion Database at the USDA’s National Soil Survey Center in Lincoln, Neb. To help reduce future erosion, farmers can use no-till farming and plant cover crops, the researchers note. By planting cover crops during off-seasons, farmers reduce the amount of time the soil is bare, making it less vulnerable to wind and water erosion.
In the United States, no-till and similar practices to help limit erosion have been implemented at least sometimes by 51 percent of corn, cotton, soybean and wheat farmers, according to the USDA. But cover crops are only used in about 5 percent of cases where they could be, says Bruno Basso, a sustainable agriculture researcher at Michigan State University in East Lansing who wasn’t involved with the study. “It costs $40 to $50 per acre to plant a cover crop,” he says. Though some government grant funding is available, “the costs of cover crops are not supported,” and there is a need for additional incentives, he says.
To implement no-till strategies, “the farmer has to be a better manager,” says Keith Berns, a farmer who co-owns and operates Green Cover Seed, which is headquartered in Bladen, Neb. His company provides cover crop seeds and custom seed mixtures. He has also been using no-till practices for decades.
To succeed, farmers must decide what particular cover crops are most suitable for their land, when to grow them and when to kill them. Following these regimens, which can be more complicated than traditional farming, can be “difficult to do on large scales,” Berns says.
Cover crops can confer benefits such as helping farmers repair erosion and control weeds within the first year of planting. But it can take multiple years for the crops’ financial benefits to exceed their cost. Some farmers don’t even own the land they work, making it even less lucrative for them to invest in cover crops, Berns notes.
Building soil health can take half a decade, Basso says. “Agriculture is really always facing this dilemma [of] short-sighted, economically driven decisions versus longer-term sustainability of the whole enterprise.”
Recurring climate changes may have orchestrated where Homo species lived over the last 2 million years and how humankind evolved.
Ups and downs in temperature, rainfall and plant growth promoted ancient hominid migrations within and out of Africa that fostered an ability to survive in unfamiliar environments, say climate physicist and oceanographer Axel Timmermann and colleagues. Based on how the timing of ancient climate variations matched up with the comings and goings of different fossil Homo species, the researchers generated a novel — and controversial — outline of human evolution. Timmermann, of Pusan National University in Busan, South Korea, and his team present that scenario April 13 in Nature.
Here’s how these scientists tell the story of humankind, starting roughly 2 million years ago. By that time, Homo erectus had already begun to roam outside Africa, while an East African species called H. ergaster stuck close to its home region. H. ergaster probably evolved into a disputed East African species called H. heidelbergensis, which split into southern and northern branches between 850,000 and 600,000 years ago. These migrations coincided with warmer, survival-enhancing climate shifts that occur every 20,000 to 100,000 years due to variations in Earth’s orbit and tilt that modify how much sunlight reaches the planet. Then, after traveling north to Eurasia, H. heidelbergensis possibly gave rise to Denisovans around 430,000 years ago, the researchers say. And in central Europe, harsh habitats created by recurring ice ages spurred the evolution of H. heidelbergensis into Neandertals between 400,000 and 300,000 years ago. Finally, in southern Africa between 310,000 and 200,000 years ago, increasingly harsh environmental conditions accompanied a transition from H. heidelbergensis to H. sapiens, who later moved out of Africa.
But some researchers contend that H. heidelbergensis, as defined by its advocates, contains too many hard-to-categorize fossils to qualify as a species.
An alternative view to the newly proposed scenario suggests that, during the time that H. heidelbergensis allegedly lived, closely related Homo populations periodically split up, reorganized and bred with outsiders, without necessarily operating as distinct biological species (SN: 12/13/21). In this view, mating among H. sapiens groups across Africa starting as early as 500,000 years ago eventually produced a physical makeup typical of people today. If so, that would undermine the validity of a neatly branching evolutionary tree of Homo species leading up to H. sapiens, as proposed by Timmermann’s group.
The new scenario derives from a computer simulation of the probable climate over the last 2 million years, in 1,000-year intervals, across Africa, Asia and Europe. The researchers then examined the relationship between simulated predictions of what ancient habitats were like in those regions and the dates of known hominid fossil and archaeological sites. Those sites range in age from around 2 million to 30,000 years old.
Previous fossil evidence indicates that H. erectus spread as far as East Asia and Java (SN: 12/18/19). Timmermann’s climate simulations suggest that H. erectus, as well as H. heidelbergensis and H. sapiens, adapted to increasingly diverse habitats during extended travels. Those migrations stimulated brain growth and cultural innovations that “may have made [all three species] the global wanderers that they were,” Timmermann says.
The new habitat simulations also indicate that H. sapiens was particularly good at adjusting to hot, dry regions, such as northeastern Africa and the Arabian Peninsula.
Climate, habitat and fossil data weren’t sufficient to include additional proposed Homo species in the new evolutionary model, including H. floresiensis in Indonesia (SN: 3/30/16) and H. naledi in South Africa (SN: 5/9/17).
It has proven difficult to show more definitively that ancient environmental changes caused transitions in hominid evolution. For instance, a previous proposal that abrupt climate shifts resulted in rainy, resource-rich stretches of southern Africa’s coast, creating conditions where H. sapiens then evolved (SN: 3/31/21), still lacks sufficient climate, fossil and other archaeological evidence.
Paleoanthropologist Rick Potts of the Smithsonian Institution in Washington, D.C., has developed another influential theory about how climate fluctuations influenced human evolution that’s still open to debate. A series of climate-driven booms and busts in resource availability, starting around 400,000 years ago in East Africa, resulted in H. sapiens evolving as a species with a keen ability to survive in unpredictably shifting environments, Potts argues (SN: 10/21/20). But the new model indicates that ancient H. sapiens often migrated into novel but relatively stable environments, Timmermann says, undermining support for Potts’ hypothesis, known as variability selection.
The new findings need to be compared with long-term environmental records at several well-studied fossil sites in Africa and East Asia before rendering a verdict on variability selection, Potts says.
The new model “provides a great framework” to evaluate ideas such as variability selection, says paleoclimatologist Rachel Lupien of Lamont-Doherty Earth Observatory in Palisades, N.Y. That’s especially true, Lupien says, if researchers can specify whether climate and ecosystem changes that played out over tens or hundreds of years were closely linked to ancient Homo migrations.
For now, much remains obscured on the ancient landscape of human evolution.
