史前牙齒中的蛋白質揭示出石器時代早期人類物種之間有那樣的性接觸（2/2）

Recently CNN.com reported the following:

What proteins in prehistoric teeth reveal about Stone Age sex between early human species (2/2)

CNN- By Katie Hunt

UPDATED MAY 14, 2026

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‘Ghost lineage’

Geneticists knew that Denisovans had some ancestry from an unknown “ghost lineage” with no DNA match, and Homo erectus was one possible candidate, said Eduard Pop, a research scientist at Naturalis Biodiversity Center in Leiden, Netherlands, via email.

“This study strengthens that link,” said Pop, who is working with researchers to understand if protein information is preserved in Homo erectus fossils found in Indonesia.

“It suggests that East Asian Homo erectus-related populations may have contributed genetically to Denisovans, and through them indirectly to some modern humans,” he said.

“So it fits with a view of human evolution in Asia as a network of populations that sometimes overlapped and interbred, rather than a set of clean, isolated branches.”

From the protein information, the researchers were also able to determine the sex of the fossils — five males and one female — by identifying a sex-specific marker in a tooth enamel gene on the Y chromosome.

Work published in 2020 retrieved proteins from an early Homo erectus fossil found in Dmanisi, Georgia, but, unlike the new study, Pop noted it didn’t reveal any detailed information about how the species sits in relation to other hominins.

The fossils came from three sites in central and northern China: Zhoukoudian, Hexian and Sunjiadong. The country has a long history of the discovery of Homo erectus fossils. In the 1920s and 1930s, hundreds of fossils were excavated from Zhoukoudian, including several skulls. The remains became known as Peking Man. However, the fossils, packed in two wooden crates, went missing during the chaos of World War II.

The tooth from Zhoukoudian used in this latest research was discovered during an excavation from 1949 to 1951, the study noted.

Homo erectus was the earliest human species to have body proportions similar to those of Homo sapiens. They had an upright stance, a large face with a protruding brow and no chin. Fossil evidence for Homo erectus stretches over more than 1.5 million years, far longer than the 400,000 years that Homo sapiens have been around, making the former species by far the longest surviving of all human relatives, according to London’s Natural History Museum.

The new study relied heavily on the hypothesis that Denisovans and Homo erectus interbred, but the Smithsonian’s McRae said an alternative explanation could be possible given that the Homo erectus fossils were 400,000 years old and the oldest known Denisovan fossil included in the study is the Dragon Man cranium, which is 150,000 to 300,000 years old.

“Even at the closest, there is still a 100,000-year gap between the two species, meaning that an ancestor-descendant relationship could be an alternative possibility,” he said via email, suggesting that Denisovans perhaps evolved directly from Homo erectus rather than coexisting.

“Transmission of the amino acid variant through interbreeding is certainly possible, I would even say plausible, but archaeological evidence could help confirm a closer connection between the two groups,” he added.

Fu agreed the information her team gleaned from tooth enamel was not detailed enough to understand how Homo erectus is related to other humans. Only DNA would really provide that granular information, she said. Fu described the study’s finding as a “stone thrown in a pool with a big splash,” opening up new questions for future research.

Translation

史前牙齒中的蛋白質揭示出石器時代早期人類物種之間有那樣的性接觸（2/2）

（繼續）

 “幽靈譜系”

荷蘭的萊頓自然生物多樣性中心的研究科學家Eduard Pop透過電子郵件表示，遺傳學家早就知道丹尼索瓦人擁有來自未知的「幽靈譜系」的祖先，該譜系沒有DNA比對吻合，而直立人是其中一個可能的吻合者。

目前正與研究人員合作，研究在印尼發現的直立人化石中是否保存了蛋白質資訊的Pop說:「這項研究加強了這種相信關聯存在」。

他說:「這表明，東亞與直立人相關的群體可能在基因上對丹尼索瓦人有所提供，並透過丹尼索瓦人間接地影響了一些現代人類」。

「因此，這與在亞洲，人類進化是一個群體網絡（這些群體有時會重疊並相互交配）的觀點相符，而不是一系列清晰、獨立的分支。”

研究人員利用蛋白質訊息，透過識別Y染色體上琺瑯質基因中的性別特異性標記，確定了化石的性別 - 五名男性和一名女性。

2020年發表的一項研究從格魯吉亞Dmanisi發現的一具早期直立人化石中提取了蛋白質。但Pop指出，與這項新研究不同之處是，該研究並未揭示該物種與其他原始人類物種之間關係的任何詳細信息。

這些化石來自中國中北部三個地點：週口店、河縣和孫家洞。中國有著悠久的直立人化石發現歷史。在1920年代和1930年代，周口店出土了數百件化石，其中包括幾個頭骨。這些遺骸被稱為北京猿人。然而，這些裝在兩個木箱裡的化石在二戰的混亂中遺失了。

研究報告指出，這項最新研究中使用的周口店牙齒是發現於1949年至1951年的一次考古發掘中。

直立人是最早擁有與智人相似體型比例的人類物種。他們直立行走，臉部較大，眉毛突出，沒有下巴。據倫敦自然歷史博物館稱，直立人的化石證據可以追溯到150多萬年前，遠遠長於智人存在的40萬年，這使得直立人成為迄今為止所有人類近親中存活時間最長的物種。

這項新研究主要依賴丹尼索瓦人和直立人雜交的假設，但Smithsonian博物館的McRae表示，考慮到直立人化石距今有40萬年，而研究中已知的最古老的丹尼索瓦人化石是距今15萬至30萬年的「龍人」頭骨，因此事情可以有另一種解釋。

他透過電子郵件表示:「即使是最接近的情况，這兩個物種之間仍然存在10萬年的差距，這意味著祖先-後代關係也可能是有另一種可能性」，並暗示丹尼索瓦人或許直接從直立人進化而來，而非與直立人共存。

他補充道:「透過雜交傳播氨基酸變異當然是可能的，我什至認為這種可能性很大，但考古證據或許有助於證實這兩個群體之間有更緊密的聯繫」。

Fu女士也認同，她的團隊從琺瑯質中提取的資訊不足以詳細了解直立人與其他人類的親緣關係。她說，只有DNA才能真正提供這種細緻的資訊。Fu女士將目前這項研究的發現比作“投入池塘的石子激起的巨浪” ，為未來的研究提出了新的問題。

So, a prehistoric human known as Homo erectus was the first of our forerunners to leave Africa and to roam the planet for almost 2 million years. But with scarce genetic material available to study, the species remains a major mystery in human origins. Now, scientists have evidence to indicate a molecular link between Homo erectus and later human species. Apparently, this revelation is not detailed enough to understand how Homo erectus is related to other humans. Yet, this new study’s finding has opened up new questions for future research.