tenda Health

The race to fertilize an egg is not just about speed. The egg has a say in which sperm gets in, and it’s not always the first one. A new study shows how the egg uses chemical signals to attract and select the best sperm for the job.

Researchers from Sweden and the UK¹ found that the egg releases substances that guide the sperm towards it. This process, called chemotaxis, helps the egg choose the most suitable sperm from millions of candidates. The study, published in The Royal Society², challenges the idea that the fastest sperm wins the prize.

Chemotaxis is not unique to humans. It has been observed in some animals, such as sea urchins and mice³. But it is not clear how common it is or how it affects fertility. The researchers hope that their findings will improve assisted reproduction techniques, such as IVF⁴, by mimicking nature’s way of sperm selection.

Sperm quality is important for successful fertilization and healthy offspring⁵. But not all sperm are equal. Some have defects in their shape, movement or DNA that reduce their chances of reaching or penetrating the egg. The egg’s ability to filter out these faulty sperm may be a form of sexual selection that enhances reproductive fitness.

Source:
(1).https://www.news-medical.net/news/20200611/The-egg-decides-which-sperm-fertilizes-it.aspx#:~:text=The%20team%20from%20Stockholm%20University%20and%20Manchester%20University,of%20sperms%20has%20been%20seen%20in%20some%20species.. https://www.news-medical.net/news/20200611/The-egg-decides-which-sperm-fertilizes-it.aspx.
(2) Egg meets sperm (article) | Embryology | Khan Academy. https://www.khanacademy.org/test-prep/mcat/cells/embryology/a/egg-meets-sperm.
(3) Sperm selection in natural conception: what can we learn from Mother …. https://academic.oup.com/humupd/article/21/6/711/629284.
(4) Sperm Selection for IVF | ICSI, PICSI, Nanobeads | MCRM Fertility. https://www.mcrmfertility.com/treatment-options/in-vitro-fertilization-ivf/sperm-selection/.
(5) Sexual selection and the evolution of sperm quality – PubMed. https://pubmed.ncbi.nlm.nih.gov/25323970/.
(6) Sexual selection and the evolution of sperm quality. https://academic.oup.com/molehr/article/20/12/1180/1062336.