Academician Wu Xinzhi: Spending a lifetime to get closer to the truth

The following article is from China Science Daily, author Hu Minqi

Wu Xinzhi, an academician of the Chinese Academy of Sciences, has spent his entire academic career focusing on one question: where do we come from? It is this core difficulty in paleoanthropology that has made him willing to stay in the controversial area of ​​an unpopular discipline, and he has become more and more courageous as he fights.

He is persistent but not paranoid. He defends his academic views, but as long as the evidence is solid, he will also revise his research conclusions calmly without any burden.

"Hypothesis is not equal to truth." In order to get infinitely close to the truth of history, he spent his entire life looking for more fossil evidence, and he was happy to do so until the evening of December 4, 2021, when his 93-year-old life came to an end.

Wu Xinzhi observed the skull of Liujiang Man in November 2012. Photo courtesy of Liu Wu

"Opposing" the mainstream theory

Since the mid-1980s, research and debate on the origins of modern humans have been at the forefront and hot topic of international paleoanthropology research.

There are two views on the origin of modern humans that have long been in confrontation: one is the African origin theory, and the other is the multi-regional origin theory.

The former supports the view that all modern humans evolved from Homo sapiens who emerged from Africa and replaced the local archaic humans in different regions to become the dominant species, while the latter believes that Homo erectus evolved into Homo sapiens independently in various regions.

Wu Xinzhi was one of the proponents of the multi-regional origin theory.

In the 1980s, Wu Xinzhi and scholars from the United States and Australia analyzed and demonstrated the evolutionary patterns of ancient humans in East Asia and Southeast Asia-Pacific based on the fossil evidence available at the time.

In a paper published in 1984, they listed fossil morphological evidence supporting the continuous evolution of ancient humans in this region, thereby establishing the "multi-regional evolution theory" of the origin of modern humans.

However, internationally, the origin of modern humans in East Asia has long been a neglected issue, and the African origin theory has occupied an absolute mainstream position because it had very important molecular biological evidence at the time - the Eve theory.

Several scientists from the University of California, Berkeley, took advantage of the fact that mitochondrial DNA is only inherited from the mother, so the tracing process will eventually lead to the characteristics of a single female ancestor. Based on the known mutation rate of mitochondrial DNA, they believed that the mitochondrial DNA of all babies could be traced back to a woman who lived in Africa about 200,000 years ago, the so-called "Eve."

For nearly 40 years since then, Wu Xinzhi has been "playing a rival tune" to the African origin theory, and his performance has become more and more courageous.

Based on the comparative analysis of the characteristics of a large number of ancient human fossils, Wu Xinzhi demonstrated from the aspects of the chronological order of Chinese ancient human fossils, common morphological characteristics, gradual changes, heterogeneity of morphological characteristics, mosaicism, genetic exchanges with ancient humans in other regions, and ancient cultural evidence that the evolution of ancient humans in China was mainly continuous, and that there was increasing genetic exchanges with ancient humans in other parts of the world.

He also listed 11 common characteristics that support the continuous evolution of ancient humans in China, pointing out that these common characteristics persisted for longer or shorter periods throughout the evolution of ancient humans in China.

Based on these studies, he formally proposed a new hypothesis about the evolution of Chinese humans in 1998 - continuous evolution with hybridization, which clearly pointed out that the evolutionary pattern of ancient humans in China was mainly continuous evolution, with genetic exchanges with surrounding ancient humans.

This theory has become an important part of the multi-regional evolution theory.

“He just loves this job so much.”

Entering the 21st century, the theory that indigenous ancient humans around the world were completely replaced by African Homo sapiens began to be questioned by a lot of evidence.

In particular, in 2010, Svante Pääbo, director of the Max Planck Institute for Evolutionary Anthropology in Germany, published the world's first draft of the Neanderthal genome, directly comparing the Neanderthal genome with the genome of modern humans for the first time.

This study proves that, with the exception of Africans, the genetic makeup of today's Eurasians all contains 1% to 4% Neanderthal genetic components, and this ancient human type has never been completely replaced.

Not only that, with the emergence of new ancient human fossils in China in the past 20 years, Wu Xinzhi discovered that the fossils of Homo erectus, early Homo sapiens, and modern humans in East Asia have continuity in their evolutionary time distribution, and exist in both the north and the south in spatial distribution.

He also discovered that ancient humans in China also had common characteristics in physical traits and cultural relics.

Therefore, he insisted that in the process of Homo sapiens moving out of Africa, they constantly interbred and hybridized with local ancient humans, and together they evolved towards modern humans. There should not be only one pattern for the origin of modern humans around the world.

Europe is mainly from Africa, supplemented by local Neanderthals, East Asia is probably mainly from locals, supplemented by foreigners, and Australia is mainly from Indonesia, supplemented by other regions. In short, the evolutionary patterns of different regions are not the same.

However, due to the progress of ancient DNA technology, there is currently no direct molecular biological evidence to prove the hypothesis of continuous evolution of East Asians, and this controversy is far from being settled.

But Wu Xinzhi is well aware that paleontology is a special discipline that relies heavily on fossil evidence. With the emergence of new fossil evidence and the updating of research methods, existing conclusions may be overturned at any time.

Liu Wu, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, has studied and worked under the guidance of Wu Xinzhi for more than 30 years. In his memory, "Mr. Wu often said that one must get used to controversy when doing paleoanthropology research.

He also often reminds us that various existing theories are just hypotheses, not truth, let alone historical reality.

What we are doing is just getting closer to the truth, but no one knows when we will get there."

What impressed Liu Wu deeply was that Wu Xinzhi always added a special "note" in his research papers, such as - the comparative data of many projects are very limited at present, which may cause some illusions and lead to misjudgment to a certain extent.

The author anticipates that the emergence of new fossils and new data may necessitate revisions, large or small, of the following analysis.

This is enough to show that "speaking with evidence in everything" is Wu Xinzhi's consistent principle.

In Liu Wu's eyes, compared with the results, what Wu Xinzhi really values ​​is an open mind, independent thinking and judgment, rather than a blind attitude towards scholarship.

As he wrote in the preface to the Chinese version of Pabo's autobiography: "He and I belong to different disciplines, and both explore the origins of modern humans. Although I cannot fully agree with his views, I am deeply moved by his fruitful contributions and the hard work he described in the book." This is both respect for the "opponent" and respect for science.

Until the end of his life, Wu Xinzhi remained a minority in the controversial area of ​​paleoanthropology research.

In the past, he has been criticized for his persistent pursuit due to narrow nationalism.

"Mr. Wu has never talked to me about this topic. He just works hard without any extra response." Liu Wu knows the purity of Mr. Wu's heart, "He just loves this job too much!"

Being both a commander and a fighter

"Mr. Wu not only founded and developed the 'multi-regional evolution theory' of the origin of modern humans, but also, during his academic career, several branches of Chinese paleoanthropology and physical anthropology developed under his direct participation and guidance, promoting the production of more results," Liu Wu emphasized in the interview.

"Mr. Wu has participated in and directed the production of the Peking Man female restoration, the Upper Cave Man restoration, the Maba Man restoration, and the Nanjing Man skull restoration and restoration. It can be said that he is a pioneer and leader in the field of skull facial restoration of ancient humans, ancient populations, and modern humans in China. In the 1980s, he also pioneered forensic anthropology research in China and trained relevant talents."

Wu Xinzhi also spared no effort to push the academic topic of "Where do humans come from" into the mainstream discourse system, allowing the media, the public, and scientific research management departments to pay attention and attach importance to it, thereby enhancing the influence of this discipline.

Especially after 2000, he spent a lot of time on popular science work besides scientific research, giving reports, lectures, writing articles... He also published two popular science books, "Footprints of Human Evolution" and "Exploring Ancient Humans", demonstrating the social responsibility of an intellectual.

In 2000, Wu Xiujie came to the Institute of Vertebrate Paleontology and Paleoanthropology for a postgraduate interview, and the chief examiner at that time was Wu Xinzhi. "I was a little nervous when I heard that Professor Wu was an academician, but when I saw his kind face, I relaxed."

Wu Xiujie, now a researcher, said that this scene seemed to be right in front of him, because Wu Xinzhi's face was always the same when facing his students.

"Teacher Wu always takes good care of his students, teaches them everything he knows, and is very patient. He especially likes us to ask questions, and he will display his various specimens and talk for hours without getting bored."

Wu Xiujie told China Science Daily, "When he received students' essays, he corrected them very carefully, weighing every word and sentence, even the punctuation marks."

What moved the students most was that even at the age of over 80, Wu Xinzhi never "bothered" them to run errands, and even did small things like printing documents himself.

"I'm old and not as busy as you are. You just focus on your own work. You don't need to worry about what I can do myself." Wu Xiujie's memories are full of warmth.

"Mr. Wu, who always leads the direction of the discipline and personally and meticulously handles all kinds of complicated tasks, and is both a commander and a fighter, is a role model for our entire lives!" Liu Wu said.

Source: China Science Daily