Scientists have made a groundbreaking discovery by generating the first complete chromosome sequences from non-human primates. The research, funded by the National Institutes of Health, sheds light on the species diversity and evolution of six primate species.

Published in Nature, the study compared the sequences of the ape chromosomes to human X and Y chromosomes to gain insights into their evolutionary histories. The researchers focused on the X and Y chromosomes, crucial for sexual development and fertility, among other biological functions.

The team sequenced chromosomes from five great ape species – chimpanzee, bonobo, gorilla, Bornean and Sumatran orangutans – as well as one more distantly related primate species, the siamang gibbon. These sequences revealed significant variation between the Y chromosomes of different species, indicating rapid evolution and uncovering previously unstudied regions of great ape genomes.

Brandon Pickett, Ph.D., a postdoctoral fellow at the National Human Genome Research Institute, highlighted the importance of these chromosome sequences in providing new information. He noted that while the chimpanzee genome sequence was fairly complete, gaps still existed, particularly in regions of repetitive DNA.

Analysis of the new sequences showed that a significant portion of the X and Y chromosomes are composed of repetitive DNA sequences, posing challenges for characterization. Advances in DNA sequencing technologies and analysis methods have enabled the study of repetitive DNA, offering new insights into primate genomes.

By comparing the ape chromosomes to human X and Y chromosomes, the researchers traced their evolutionary histories. The great ape Y chromosomes, similar to human counterparts, have fewer genes compared to the X chromosomes. Using alignment, a computational method, the researchers identified regions of the chromosome that have remained relatively stable over evolution, highlighting the impact of different evolutionary pressures on the genome.

Overall, the study revealed that over 90% of the ape X chromosome sequences align with the human X chromosome, underscoring the genetic similarities between these species. The new chromosome sequences from non-human primates offer valuable insights into human evolution and the genetic relationships between primates and humans.