CNV variation in the great apes

An awesome comparison made possible by having the great ape genomes! These researchers looked at copy number variations (CNVs) in the great apes and in this way compared genomic structural variation across chimps, bonobos, gorillas and orangutans. They found signatures of different, species specific selection pressures as follows: purifying selection in the gorilla, positive selection for the fixation of structural variants in the orangutan, and relaxed purifying selection with high mutation rates in chimpanzees and bonobos. A surprising result is that chimpanzees and bonobos share more CNVs with gorillas than they do with each other (figure shown below). This is explained by homoplasy. This analysis was done on a total of 51 individuals from the four species by applying a comparative genomic hybridization of their samples onto the reference genome for each species. *Discussion question: I wonder what this same analysis would look like in 10 years after we get higher quality reference genomes for each of these species! How much does everyone trust this result given the state of the genomes today? Brenda, maybe you can comment on this better than any of us can....*