A team of researchers from Penn State, the National Human Genome Research Institute, and the University of Washington have produced new complete reference genomes for the sex chromosomes of five great ape species and one lesser ape species. These genomes highlight rapid changes on the male-specific Y chromosome among ape species and shed light on the evolution of sex chromosomes and diseases related to genes on these chromosomes in apes and humans. The study, published in Nature, provides a roadmap for future studies of sex chromosomes and their evolution.
The newly generated reference genomes act as representative examples for future studies of these species, providing insights into their genetic makeup and facilitating further research. The researchers found that the Y chromosome varies greatly across ape species compared to the X chromosome and is subject to purifying natural selection, which protects genetic information by removing harmful mutations. By leveraging experimental and computational methods developed by the Human Telomere-to-Telomere Consortium, the team was able to determine complete sequences for the sex chromosomes of the great apes.
The team produced complete sex chromosome sequences for five great ape species and one lesser ape species, which had incomplete or non-existent sequences before. The new study reveals that the Y chromosome is more variable than the X chromosome across the ape species in terms of size, shared DNA sequences, and repetitive elements. Despite shrinking in size and losing genes, the Y chromosome has evolved to survive through genetic redundancy and palindrome structures that allow for genetic exchange and mutation correction.
The researchers found that genes on the Y chromosome utilize genetic redundancy and palindromes to remain intact and compensate for mutations, ensuring the survival of the Y chromosome. By studying the genetic variation within gorilla and chimpanzee populations, the researchers identified additional signatures of purifying selection on the Y chromosome, confirming the role of this type of natural selection in the evolution of sex chromosomes. The reference genomes generated by the team will enable future studies of primate evolution and human diseases.
The collaborative research effort involved bioinformatic techniques and evolutionary analyses to uncover the evolutionary processes at play on the sex chromosomes of great apes. The reference genomes produced by the team will serve as valuable tools for understanding primate evolution and genetic diseases. Funding from the National Institutes of Health supported this research, which provides valuable insights into the evolution of sex chromosomes and their role in ape species. The study enhances our understanding of sex chromosome evolution and its implications for human health and reproduction.