Burgoyne P S, Thornhill A R, Boudrean S K, Darling S M, Bishop C E, Evans E P
National Institute for Medical Research, Ridgeway, London, U.K.
Philos Trans R Soc Lond B Biol Sci. 1995 Nov 29;350(1333):253-60 discussion 260-1. doi: 10.1098/rstb.1995.0159.
There is now a substantial body of data showing that in eutherian mammals (mouse, rat, cow and man) XY conceptuses are developmentally more advanced (and consequently larger) than XX conceptuses of equivalent gestational age. This developmental difference is already discernible in the preimplantation period and it has been suggested that the more advanced development of XY embryos may be a consequence of the preimplantation expression of Y chromosomal genes such as Sry or Zfy. In the present paper sex-chromosomally variant mice were used to analyse the genetic basis of XX-XY differences as manifest at 10.5 days post coitum. The results show that the XX-XY difference is due to a combination of a Y chromosome effect and an effect of the difference in X chromosome constitution (2X v 1X). The Y effect is not dependent on the presence of Sry. In the light of this and other studies, it is concluded that the Y chromosome of most mouse strains carries a factor which accelerates preimplantation development and that the resulting developmental advantage is carried over into the postimplantation period. The retarding effect of two X chromosomes is then superimposed on this Y effect subsequent to the blastocyst stage but prior to 9.5 days post coitum.
现在有大量数据表明，在真兽亚纲哺乳动物（小鼠、大鼠、牛和人类）中，相同胎龄的XY胚胎在发育上比XX胚胎更超前（因此也更大）。这种发育差异在植入前阶段就已明显，有人提出XY胚胎更超前的发育可能是Y染色体基因（如Sry或Zfy）在植入前表达的结果。在本文中，利用性染色体变异小鼠分析了在交配后10.5天时XX与XY差异所体现的遗传基础。结果表明，XX与XY的差异是Y染色体效应和X染色体组成差异（2条X对1条X）共同作用的结果。Y染色体的效应不依赖于Sry的存在。鉴于此研究及其他研究，得出的结论是，大多数小鼠品系的Y染色体携带一种能加速植入前发育的因子，由此产生的发育优势会延续到植入后阶段。两条X染色体的延缓效应在囊胚期之后、交配后9.5天之前叠加在这种Y染色体效应之上。
