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.
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.
ReplyDeletePosted By: Forootan Alizadehasil
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.
ReplyDeletePosted by: Ashley Geary