This is a very intriguing finding! However, I do wonder if we should assume AMELY is present in every male individual and in every species. It's present in Neanderthals, Denisovans, Paranthropus robustus, and sapiens (and I presume many more species) but when I hear about a new protein study I'm reminded of the 2022 paper by Laurits Skov and colleagues. https://doi.org/10.1038/s41586-022-05283-y
They found that Mezmaiskaya 2, a Neanderthal, was missing the AMELY gene in his genome. Genetically he was a male but proteomically researches would have regarded him as female. How common is this across individuals? Is it possible that the males across a hominin lineage, such as H. naledi, lost the AMELY gene in their Y-chromosome? Or was this deletion in Mezmaiskaya 2 simply another example of genetic drift overtaking the last members of a waning lineage?
It's amazing that naledi is serving up surprises all these years later! I'm still hoping one day DNA will be recovered.
We go into this alternative hypothesis to some degree in the paper because if AMELY or a significant part of the Y chromosome were deleted in H. naledi we might observe the same molecular result. Deletions of Y are much rarer than being female, with the highest observed frequency in any population of humans under 2% of men, so on net the probability of this hypothesis is much lower than sex bias in the sample. The morphological line of data is particularly valuable.
This is a very intriguing finding! However, I do wonder if we should assume AMELY is present in every male individual and in every species. It's present in Neanderthals, Denisovans, Paranthropus robustus, and sapiens (and I presume many more species) but when I hear about a new protein study I'm reminded of the 2022 paper by Laurits Skov and colleagues. https://doi.org/10.1038/s41586-022-05283-y
They found that Mezmaiskaya 2, a Neanderthal, was missing the AMELY gene in his genome. Genetically he was a male but proteomically researches would have regarded him as female. How common is this across individuals? Is it possible that the males across a hominin lineage, such as H. naledi, lost the AMELY gene in their Y-chromosome? Or was this deletion in Mezmaiskaya 2 simply another example of genetic drift overtaking the last members of a waning lineage?
It's amazing that naledi is serving up surprises all these years later! I'm still hoping one day DNA will be recovered.
We go into this alternative hypothesis to some degree in the paper because if AMELY or a significant part of the Y chromosome were deleted in H. naledi we might observe the same molecular result. Deletions of Y are much rarer than being female, with the highest observed frequency in any population of humans under 2% of men, so on net the probability of this hypothesis is much lower than sex bias in the sample. The morphological line of data is particularly valuable.