PgmNr M5054: Rapid evolution of co-amplified X and Y chromosome genes and genomic structures in mice.

Authors:
A. Kruger; J. Mueller


Institutes
University of Michigan, Ann Arbor, MI.


Abstract:

The mammalian X and Y chromosome have diverged considerably since their evolutionary origins as autosomes.  The mouse X and Y Chromosome, however, have undergone convergent evolution by independently acquiring and co-amplifying three gene families not present on the human sex chromosomes.  Here we examine the evolutionary dynamics of these three X-Y co-amplified gene families and their genomic structures in rodents.  We find that they were acquired via transposition and retrotransposition events followed by subsequent amplification.  Our between species comparison of the three X-Y co-amplified gene families reveals they are among the most rapidly evolving genes on the rodent sex chromosomes.   Moreover, comparison of their gene family members sequence divergence within mice highlights distinct protein regions under strong positive selection.  Together with the rapid evolution of their protein-coding sequences, the genomic structures within which these gene families are harbored vary significantly in copy number.  By tracking the evolutionary trajectory of the three X-Y co-amplified gene families we are gaining insights into the coevolution of their sequence diversification and massive amplification.