Scientists are reporting that after studying the multi-cellular green alga, Volvox carteri, they have possibly found the genetic basis of the male and female sexes, thus exemplifying how they evolved from a primitive mating system in a one-celled relative. The research study was led by James Umen, Ph.D., who is an Associate Member of the Enterprise Institute for Renewable Fuels at the Danforth Science Center.
He and his group discovered the dominant governing gene for sex determination in Volvox and saw that it had gained other functions when matched to a related gene in a close relative known as Chlamydomonas reinhardtii. However this alga does not have tangibly distinguishable sexes. These findings have been printed up in the most recent edition of the science journal PLOS Biology, and propose a potential design for how sexes in multi-cellular organisms such as animals and plants might have come to be. By opposing the case in plants and animals, whose uni-cellular ancestors are remotely related, male and female sexes in Volvox evolved fairly recently yet how the two sexes evolved in the first place has been a long biological mystery.
However due to a simple genetic engineering trick which caused female Volvox carteri alga to create sperm and males to make eggs. The process showed the development of males and females were much more forthright than once believed. The majority of life forms seen each day contain millions of cells. Whether they are in the form of chirping crickets or a strong elm tree, they all have many different kind of cells and at least two different sexes. However life on Earth did not begin that way. For most of the world’s past, life was only single celled organisms. It has been only fairly recently that life sprang from one cell to many different many kinds.
Developing at the same time as multicellularity was sexual reproduction. Single-celled organisms commonly reproduce by just dividing into two. Multi-cellular creatures are unable to do such a thing, so they turned to sex to reproduce. The change between simple cell division and more complex sexual reproduction was traditionally thought to have been a complicated affair.
V. carteri‘s mating system was more complicated than that of C. reinhardtii and other one celled organisms, it had sperm-producing males and egg-producing females. They tested the MID gene by turning it off and on and it seemed to cause females to make sperm and males to create eggs. Various other scientists have stated that this information on how the sexes evolved in this group of organisms might aid in better understanding the development of sexes across all of life on the planet.
Although the MID genes from each algae species are related, the Chlamydomonas MID gene cannot be used in place of the Volvox MID. In finding a top controlling gene for each sex in this green algae group shows that each of these reproduction forms share a mutual genetic foundation. It also hints that a comparable evolutionary set-up may lie below the origin of sexes in all multi-cellular lines.
Repeating: scientists are reporting that after studying the multi-cellular green alga, Volvox carteri, they have possibly found the genetic basis of the male and female sexes, thus exemplifying how they evolved from a primitive mating system in a one-celled relative.
By Kimberly Ruble