Abstract for presentation at 11th International Congress of Human Genetics

Comparative analysis of chimpanzee and human Y chromosomes unveils complex evolutionary pathway

  • Yoko Kuroki, RIKEN Genomic Sciences Center, Japan
  • Dr Atsushi Toyoda, RIKEN Genomic Sciences Center, Japan
  • Dr Hideki Noguchi, RIKEN Genomic Sciences Center, Japan
  • Todd Taylor, RIKEN Genomic Sciences Center, Japan
  • Dr Takehiko Itoh, Mitsubishi Research Institute, Japan
  • Dae-Soo Kim, KRIBB Genome Research Center, Korea
  • Dae-Won Kim, KRIBB Genome Research Center, Korea
  • Sang-Haeng Choi, KRIBB Genome Research Center, Korea
  • Il-Chul Kim, KRIBB Genome Research Center, Korea
  • Han Ho Choi, KRIBB Genome Research Center, Korea
  • Yong Sung Kim, KRIBB Genome Research Center, Korea
  • Yoko Satta, The Graduate University for Advanced Studies, Japan
  • Naruya Saitou, National Institute of Genetics, Japan
  • Tomoyuki Yamada, The University of Tokyo, Japan
  • Shinichi Morishita, The University of Tokyo, Japan
  • Dr Yoshiyuki Sakaki, RIKEN Genomic Sciences Center, Japan
  • Prof Hong-Seog Park, KRIBB Genome Research Center, Korea
  • Prof Asao Fujiyama, RIKEN Genomic Sciences Center, Japan

    • The mammalian Y chromosome has unique characteristics compared to the autosomal or X chromosomes. Here we report the finished sequence of chimpanzee Y chromosome (PTRY) including 271 kb of the Y-specific pseudoautosomal region 1 (PAR1) and 12.7 Mb of the male-specific region of the Y chromosome (MSY). Comparative analysis by high-quality sequence data showed the greater sequence divergence between the human Y chromosome (HSAY) and PTRY (1.78%) than between their respective whole genomes (1.23%), which confirmed the accelerated evolutionary rate of the Y chromosome. Each of the 19 PTRY protein-coding genes analyzed had at least one nonsynonymous substitution, and 11 genes had nonsynonymous substitution rates than synonymous ones, suggesting relaxation of selective constraint or positive selection or both. Although higher nucleotide divergence was observed by the comparison of HSAY and PTRY, the intra-species divergence in PTRY was lower than that of the expectation. We identified the four large-scale palindromes on the region analyzed in this study, three of them were the counterparts of human (P6+, P7 and P8) and the other was the chimpanzee-specific (CSP1). We also identified lineage-specific changes including deletion of a 200 kb fragment from the pericentromeric region of HSAY, expansion of young Alu families in HSAY, and accumulation of young L1 elements and LTR retrotransposons in PTRY. The comparison between human X chromosome and HSAY or PTRY allowed us to simulate the structure of the common ancestral Y chromosome. Reconstruction of the common ancestral Y chromosome indicates the pressure of dynamic changes that our genomes have undergone over the past 5-6 million years following speciation.

    Conference Organiser - ICMS Pty Ltd