View Full Version : The bonobo genome compared with the chimpanzee and human genomes

01-06-2016, 10:54 PM
This study is controversial because it has been often used by racists or the information being misinterpreted. So I would like to see and understand the real truth of the study. Many racists say it says that SSA Africans are closer to Bonobos than to other humans, something that I find to be not true at all. I have seen this same study being used by racists to say such. So I wonder if a person educated in biology can tell us what they mean by those graphs.

The study is here:


01-06-2016, 11:04 PM
I don't believe in racism, or even in the racist/racialist evolutionary terms, I actually want to understand the article, in order to know the true meaning of the study and put facts rather than false statements or misrepresentation of it.

01-07-2016, 12:23 AM
I'm not a trained biologist, but if these "racists" are alluding to the X/A chart as an indication of inter-species genetic proximity, I think they are reading it wrong.

Differences in female and male population history, for example, with respect to reproductive success and migration rates, are of special interest in understanding the evolution of social structure. To approach this question in the Pan ancestor, we compared the inferred ancestral population sizes of the X chromosome and the autosomes. Because two-thirds of X chromosomes are found in females whereas autosomes are split equally between the two sexes, a ratio between their effective population sizes (X/A ratio) of 0.75 is expected under random mating. The X/A ratio in the Pan ancestor, corrected for the higher mutation rate in males, is 0.83 (0.750.91) (Fig. 4 (http://www.nature.com/nature/journal/v486/n7404/full/nature11128.html#f4) and Supplementary Information (http://www.nature.com/nature/journal/v486/n7404/full/nature11128.html#supplementary-information), section 8). Similarly, we estimated an X/A ratio of 0.85 (0.790.93) for present-day bonobos using Ulindi single nucleotide polymorphisms in 200-kb windows (Supplementary Information (http://www.nature.com/nature/journal/v486/n7404/full/nature11128.html#supplementary-information), section 9). Under the assumption of random mating, this would mean that on average two females reproduce for each reproducing male. The difference in the variance of reproductive success between the sexes certainly contributes to this observation, as does the fact that whereas bonobo females often move to new groups upon maturation, males tend to stay within their natal group20 (http://www.nature.com/nature/journal/v486/n7404/full/nature11128.html?WT.ec_id=NATURE-20120628#ref20). Because both current and ancestral X/A ratios are similar to each other and also to some human groups (Fig. 4 (http://www.nature.com/nature/journal/v486/n7404/full/nature11128.html#f4)), this suggests that they may also have been typical for the ancestor shared with humans.

Essentially, the X/A ratio allegedly describes the implied mating behavior within the effective population. I would suggest that the lower X/A ratio in the European human population could be caused by (1) a low initial seed population within the group, (2) a more recent seed population within the group, (3) a gender imbalance in the seed population of the group, or (4) selective mating behavior within the group, such as a preference for life-long pair-bonding rather than random mating or multiple partners [monogamy vs. polyamy].