Human evolution: from DNA in African fossils (Introduction)

by David Turell , Sunday, June 01, 2025, 18:22 (3 days ago) @ David Turell

Using teeth to study for sex identification:

https://www.sciencenews.org/article/ancient-proteins-hominid-molecular

"An ancient, distant human cousin from southern Africa called Paranthropus robustus has for the first time revealed molecular clues to its evolutionary status.

"Protein sequences preserved in four partial P. robustus teeth from different individuals that lived roughly 2 million years ago indicate that larger and smaller fossils of this hominid species cannot always be classed as male or female, as previously thought, researchers report in the May 29 Science.

"Sequences of a protein derived from a gene located only on the Y, or male, sex chromosome in present-day humans enabled the scientists to identify two teeth as having belonged to males, molecular biologist Palesa Madupe of the University of Copenhagen and colleagues say. One of those teeth was previously thought to have come from a female, based on its small size. Closer analyses of the two teeth lacking that male-specific protein indicated that those fossils, which are around the same size as the smaller male tooth, came from females.

“Paleoanthropologists have long known that our use of tooth size to estimate sex was fraught with uncertainty, but it was the best we had,” says paleoanthropologist Paul Constantino of Saint Michael’s College in Colchester, Vt. “Being able to accurately identify the sex of fossils using proteins will be hugely impactful.”

"Proteins survive far longer in fossils than DNA does, especially in hot climates where genetic material degrades rapidly. The oldest DNA recovered in Africa dates to around 18,000 years ago.

"Analysis of another protein indicated that one of the four fossil teeth came from a P. robustus individual more distantly related to the other three species members, the researchers say.

***

"Those signs of genetic diversity suggest that distinct groups of P. robustus inhabited southern Africa, the scientists conclude. Mating among different groups may have resulted in the range of protein variants observed in the four fossilized teeth, or perhaps the tooth identified as a protein outlier came from another Paranthropus species. Protein analyses of a larger number of P. robustus specimens are needed to explore those possibilities, the researchers say."

Comment: amazing new advances in DNA studies. It seems upright forms developed early in several areas of Africa, as if we were destined to appear at some latter point.