Researchers Develop New Method for Sexing Sperm
Sperm sorting - Wikipedia
Valerie J. Grant, Lawrence W. Although contemporary methods of physically separating X from Y chromosome-bearing spermatozoa are now very efficient, overall fertility rates following the use of sex-sorted sperm are not as impressive, in spite of many attempts to improve them. At the same time, there are suggestions from evolutionary biology, and from sex allocation theory in particular, that there may need to be a modification to the chance theory of sex determination in mammals. This is because it now appears that the mammalian female could have some influence on the sex of her offspring, and furthermore, that this influence could be preconceptual. If so, this could go some way towards accounting for the putative inefficiencies in fertilization following insemination with sex-sorted sperm.
Sexed Semen: An Overview
T he mammalian X chromosome has many genes that the Y does not—a feature that has special implications for sperm, and also for scientists. The mouse X chromosome carries two protein receptors that when activated by a chemical make X-bearing sperm slower and easy to separate from Y-bearing sperm, a team of Japanese researchers has found. By sorting the gametes using this method and allowing them to fertilize oocytes in vitro, the scientists could selectively generate mouse litters with majority-female or majority-male pups, they report today August 13 in PLOS Biology. Reproductive biologist Masayuki Shimada of Hiroshima University and his colleagues initially began the research to better understand the genetic differences between X- and Y-bearing sperm and whether they could explain differences in the mobility of X- and Y-bearing sperm, which previous researchers have observed under specific in vitro conditions. Among those expressed on the X, the team became interested in two that code for cell receptors, the Toll-like receptors TLR 7 and 8.
March 11, by Dr. Sudipta Saha. Use of sexed semen in conjunction with in vitro embryo production is a potentially efficient means of obtaining offspring of predetermined sex.