Sex Identification Of Mouse And Bovine By Polymerase Chain Reaction

Sex identification in livestock embryo is an important part of livestock embryo transfer. It is to achieve desired offspring sex ratio by means of sex control through the transfer of known sex embryo. It is significant in livestock husbandry. As we all know, some of the production characteristic are limited (secretion of milk) or affected (produce of meat and hair) by the sex of livestock. With the sex control, those production characteristics can be expressed in desired sex offspring, which can accelerate the propagation of high quality dam and improve the development of livestock husbandry. Take cattle for example, selection of high quality dam, increase of the milk yield and the meat ratio can be achieved by the combination with embryo dissection, cryopreservation and sexing. In this experiment, the polymerase chain reactions (PCR) were established to identify the sex of the mouse and bovine, and the aspects which could affect the amplify results were discussed. The main contents were as follows: 1. SRY gene and ZFY-ZFX gene nestsd primers of mouse and bovine were designed respectively. 2. The tissue DNA of mouse and bovine were extracted and identified. All the results were identical with the sex of the tissues. 3. In vivo derived embryos (2-cell, 4-cell, 8-cell embryo and early morula) which were collected from superovulated mouse were identified by PCR. The conventional PCR and nested PCR,multiplex PCR were compared and the system of PCR was established. At the same time, the density of Mg²⁺ was selected from 1.5,2.5,3.0 mmol/L. The results indicated that the ratio of the identified embryos by the nested PCR (94.1%,111/118) was higher than by the conventional PCR (64.3%,36/56). And the multiplex PCR was helpful to avoid the interference of the false negative result. And the results were advantageous when the density of Mg²⁺ was 2.5mmol/L. 4. The morulae and blastocyst were collected from superovulated mouse. The morula stage embryos were cut into two parts, and few trophectoderm cells were removed from blastocyst stage embryos. The embryos were sexed by karyotype analysis and PCR. The results were that 12 of 21 embryos were identified for male, and 8 of 21 for female. The accurate rate of PCR was 95.2% (20/21). 5. Few cells (5-10 cells) from bovine were collected and identified, and the system of PCR was established. 6. The sperm, the serum, the operating solution and the operator factor were researched. And the results indicated that those factors did not result in contaminate.