(2) Selected Abstracts & Publications from Some Sub-Fields of Our Work.

Y chromosome sequence instability and sex determination in the mouse (contd).

Accepted for publication in the Journal of Genetics and Cell Biology , Volume 2 Issue 1

Structural destabilization of Y chromosomes in interspecific backcrosses is consistent with variations in epigenetic modifications. Ferez S.Nallaseth 1,2 and Zong Sheng Guo 2,3.

Introduction:

The Y chromosome (YPos) from M.d.poschiavinus is structurally unstable and functionally inactive in the C57BL/6J genome; it is stable and functional in the 129/Sv genome. Structural instability includes uncoupling of Y-linkage, deletions of sequences from the Sxr region and mobility shifts of YPos repeated

sequences, in some XYPos (High Copy, HC) littermates (Nallaseth, 1992). Here we analyze the biochemical basis of this sequence instability. The results are consistent withvariations in epigenetic modifications.

Summary:

(1) Feral Y chromosomes backcrossed into inbred strain genomes undergo epigenetic modifications that lower ds DNA stability & may mis-fold chromatin resulting in aberrant,(2)Y/Sry expression,(3) X-Y heteroduplex formation/SCE, which on resolution uncouple Y linkage &

induce deletions in Sxr, Sry & other Y loci.