Fundamentals of Sex determination in water buffalo (Bubalus bubalis)
Rakhi Sharma and Awadhesh Kishore*
Institute for Development of Technology for Rural Advancement, Mathura-281004 (INDIA)
*Sarvoday Mahavidyalaya, Chaumuhan-281406, Mathura (INDIA)
The number of chromosomes of the water buffalois 56 including one pair of sex chromosomes. Males have an X and a Y chromosome whereas females have X and X chromosomes. Sex determination by polymerase chain reaction PCR was found to be a speedy & correct with 95% accuracy at 43.8 days post fertilization increasing to 99.9% at 55.0 days.
Animal breeding, Bubalus bubalis, Chromosomes Fertilization, Genetics, PCR, Polymerase chain reaction, Sex, Sex chromosomes, Sex determination, Water buffalo, X chromosome, Y chromosome.
Sex determination is the mechanisms which select whether the bipotential embryo will build-up as male or female in a species. Sex determination ends in the development of individuals with characteristics that let them be identified as males, females, or in some cases, hermaphrodites.
Sex determination System:
Sex-determination system is a biological method that determines the development of sexual characteristics in an organism.
A chromosome is a single, long molecule of DNA. Chromosomes are highly organized structures that have genetic information in living organisms. The number of chromosomes of the water buffalo (Bubalus bubalis L.) is a controversial issue but finally it is 2n = 56 (Pchakadze, 1939). Out of them 27 pairs of autosomes & one pair of sex chromosomes. As in other mammals, males have an X as well as a Y chromosome & females have X X chromosomes. The XY sex-determination method is the sex-determination method present in buffalo The XX & XY sex-determination method is the most familiar, as it is present in buffalo. In the method, females have of the same kind of sex chromosome (XX), while males have distinct sex chromosomes (XY). The XY sex chromosomes are different in shape & size from each other.
In placental mammals, the presence of a Y chromosome determines sex. Normally, cells from females contain X chromosomes, & cells from males contain an X as well as a Y chromosome. The role of the Y chromosome in mammalian sex determination has been known since the early twentieth century. In most species, of the sex chromosomes, the X chromosome, normally occurs as a pair in gender but only singly in the other. The gender with X chromosomes is called the homogametic sex, because each of its gametes normally receives an X chromosome after meiosis. The gender with X chromosome usually also has a morphologically different sex chromosome, the Y chromosome. The X & Y chromosomes usually pair to some extent at meiosis, with the result that the XY is the heterogametic sex, with half its gametes containing an X & half containing a Y.
Polymerase chain reaction:
Sex determination by polymerase chain reaction PCR was found to be a speedy & correct method in buffalo (Rao et al., 1993). da Cruz et al., (2012) proved that the test performed at 43.8 days post fertilization would have 95% accuracy, increasing to 99% accuracy for testing at 48.4 days & 99.9% accuracy for tests at 55.0 days or later.
da Cruz, A.S.; Silva, D.C.; Costa, E.O.A.; De M-Jr., P.; da Silva, C.C.; Silva, D.M. and da Cruz, A.D. 2012. Cattle fetal sex determination by polymerase chain reaction using DNA isolated from maternal plasma. Animal Reproduction Science, 131, 1–2, 49–53.
Pchakadze, G. 1939. C.R. Acad. Sci. URSS., 24, 794.
Rao, K.B.; Pawshe, C.H. and Totey S.M. 1993. Sex determination of in vitro developed buffalo (Bubalus bubalis) embryos by DNA amplification. Mol Reprod Dev., 36, 3, 291-296.