The sequencing of HSY and its X counterpart was performed. The chromosomes size, gene content and physical size of inversions in HSY portion was different from X portion. High amount of retrotransposons were present in HSY portion. Thus HSY portion was larger in size than X portion. Two inversions namely, inversion 1 and 2 were observed in HSY and X portion.
Similar amount of repetitive sequence i.e. (80.7%) in HSY and (76.5%) in X chromosome were found therefore, the physical size of inversion 1 portion of HSY and X chromosome regions were similar.
The size of inversion 2 in HSY chromosome was more than twice that of X chromosome because of suppression of recombination accumulates high amount of repetitive sequences in HSY portion (80.2% in HSY against 60.5% in the X). A total of 9 HSY-specific genes and 7 pseudogenes were found in HSY portion and 24 X-specific genes and 4 pseudogenes were detected in X portion.
HSY portion and X counterpart sequencing resulted in 8.1 Mb and 3.5 Mb pseudomolecules, respectively. HSY and X were emerged about 7.0 million years ago