Wednesday, March 9, 2016

No need for sex...

Almost more than 50 years ago, scientists were able to discover this species of lizards (of the Aspidoscelis genus) that were able to create offspring without the male population. Since these lizards asexually reproduce, they do not exchange genetic material means no exchanging of genetic material. Without gene combination to enhance fitness for the constant changing of the environment, these lizards have a major disadvantage. It is still unclear as to why and how the species is around. However a recent study published in Nature, shows how it is possible that this all-lady lizard species still exists today.

Peter Baumann, associate investigator at the Stowers Institute for Medical Research in Kansas City, Mo., and co-author of the study, and his team who conducted the new research, have revealed that these lizards are able to maintain their genetic richness by starting off with twice the number of chromosomes as their  “sexually reproducing cousin”. Their hypothesis suggests, that at a certain point of time, there must have been a hybridization among the different sexual species which may have led to the creation of the parthenogenetic lizards and the reason for its’ genetic variation. The researchers also found that they are able to maintain the genetic diversity by not pairing their homologous chromosomes like sexual species but rather “combining” their sister chromosomes. The offspring produced will therefore have an identical set of chromosomes, hence why the need for males is no longer necessary.

These lizards in particular are found in Mexico and the southwestern part of the U.S. Unlike the other 70 known parthenogenetic species of vertebrates that are able to asexually reproduce whenever they want, this all-female lizard species has no other choice. There is still so much more to be discovered about how such asexual reproductive species come about and how they are able to survive. More studies and research is being done to further explain this evolutionary phenomenon.

Sarah Ona (Group 3)


  1. This is very interesting. The combination of the sister chromosomes explains how the lizards can have genetic diversity but I am skeptical as to how much diversity they could possibly have. I would imagine that their evolution is mostly based on favorable mutations and therefore would take an incredibly long time to see even minor changes in the species.

    Posted By: Forootan Alizadehasil

  2. I find any animal that reproduces asexually to be very interesting. The fact that they can still have genetic diversity without the exchange of genetic material is very unique and it would be interesting to do more research in this area. Researchers could find out if this kind of switch in reproduction could happen to more species than just lizards and what impact that could have on species.

    Posted by: Ashley Geary