Traut Walther
Institut für Biologie, Universität Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany.
J Genet. 2010 Sep;89(3):307-13. doi: 10.1007/s12041-010-0042-x.
The phorid fly Megaselia scalaris is a laboratory model for the turnover and early differentiation of sex chromosomes. Isolates from the field have an XY sex-determining mechanism with chromosome pair 2 acting as X and Y chromosomes. The sex chromosomes are homomorphic but display early signs of sex chromosome differentiation: a low level of molecular differences between X and Y. The male-determining function (M), maps to the distal part of the Y chromosome's short arm. In laboratory cultures, new Y chromosomes with no signs of a molecular differentiation arise at a low rate, probably by transposition of M to these chromosomes. Downstream of the primary signal, the homologue of the Drosophila doublesex (dsx) is part of the sex-determining pathway while Sex-lethal (Sxl), though structurally conserved, is not.
蚤蝇Megaselia scalaris是性染色体周转和早期分化的实验室模型。从野外分离的菌株具有XY性别决定机制，第2号染色体对作为X和Y染色体。性染色体是同形的，但显示出性染色体分化的早期迹象：X和Y之间的分子差异水平较低。雄性决定功能（M）定位于Y染色体短臂的远端。在实验室培养中，没有分子分化迹象的新Y染色体以低频率出现，可能是通过M转座到这些染色体上。在主要信号的下游，果蝇doublesex（dsx）的同源物是性别决定途径的一部分，而性别致死（Sxl）虽然在结构上保守，但并非如此。
