New discovery! The "distant relative" of modern tigers has been found

A reporter recently learned from China University of Geosciences (Wuhan) that the team of Professor Lai Xulong of the university, in collaboration with researchers at home and abroad, discovered a previously unknown and now extinct tiger genetic lineage through ancient DNA research. The relevant results were recently published in the internationally authoritative biology journal "Proceedings of the Royal Society B".

Previously, the archaeological team of Jilin University excavated a large number of ancient fossils in a cave in Da'an Town, Tonghua, Jilin, and provided some of the spotted hyena fossils to the ancient DNA research team of China University of Geosciences (Wuhan) for cooperative research. Through the analysis and identification of the remaining DNA in the fossils, the researchers unexpectedly discovered that one of the broken mandibles was not a spotted hyena, but a tiger (hereinafter referred to as "Da'an Tiger"), which is more than 43,500 years old.

Tiger fossils excavated from the karst cave in Da'an Town, Tonghua, Jilin. (Photo provided by the interviewee)

In biological classification, the evolutionary history and living conditions of tigers have received extensive attention. Studies have shown that all current tiger subspecies are derived from an ancestral population dating back about 110,000 years.

In order to explore the relationship between the "Da'an Tiger" and the various geographical subspecies of living tigers, the researchers have stepped up the work of extracting ancient DNA from the mandible fossil of the "Da'an Tiger" and constructing the second-generation sequencing library. From 24 sequencing libraries, they assembled a nearly complete mitochondrial genome and partial nuclear genome information of the "Da'an Tiger".

Based on the comparative analysis of the genetic components of the "Da'an Tiger" and all living tigers and the construction of a phylogenetic tree, it was found that the "Da'an Tiger" is different from any living tiger and belongs to a previously unknown and now extinct genetic lineage. This lineage had "parted ways" with the ancestors of living tigers about 260,000 years ago.

Research on living tigers can only reveal the evolutionary history of their direct ancestors. The determination and analysis of the Da'an tiger genome shows that during the evolution of tigers, some genetic lineages were lost, and all modern tigers are just descendants of one of these lineages.

Hand-drawn picture of a tiger. (Photo provided by the interviewee)

The researchers explained that the current Siberian tigers, South China tigers and other tigers are like cousins ​​to each other, while the "Da'an tiger" and modern tigers are distant relatives. Before the ancient DNA data was obtained, the genetic information of the extinct tiger lineage had been sealed in broken and easily misinterpreted fossils. Ancient DNA research has brought the extinct tiger lineage back to light, providing a basis for a systematic and comprehensive exploration of the evolutionary history of tigers.

Source: Xinhua News Agency

Reporter: Li Wei