Fast and reliable sex identification in early stage of gestation in Myocastor coypus.

The early knowledge of the sex may be crucial for the understanding of many features of ecological and evolutive biology. including offspring sex-rati o adjustment and evolution of breeding systems. In coypu (Myocastor coypus) , significant variation in birth sex-ratios can he observed and selective a bortion of entire litters is one of the cited mechanisms. In order to deter mine the sex of coypu embryos in the earlier stages of gestation (second we ek), we developed a molecular technique based on PCR amplification of a reg ion of the Sry, gene. These method used the combination of two sets of prim ers: one specific of the Y-chromosome; the other one, autosomal. is a posit ive control for amplification. Because of the direct amplification of embry o lysate without DNA extraction, the present sexing technique is rapid, rel atively simple and inexpensive. and presents numerous advantages for the st udy at population scale. (C) 2001 Academie des sciences/Editions scientifiq ues et medicales Elsevier SAS.