Which has a greater impact of evolution, mutations or genet

Discussion of everything related to the Theory of Evolution.

Moderators: honeev, Leonid, amiradm, BioTeam

Post Reply
alpha78
Garter
Garter
Posts: 1
Joined: Sun Oct 19, 2014 2:51 pm

Which has a greater impact of evolution, mutations or genet

Post by alpha78 » Sun Oct 19, 2014 2:57 pm

I am trying to figure out the answer to this question? There are mixed answers to this question from different sources.

Campbell's biology textbook states that mutations are rare and that large genetic variations in a population of organisms that reproduce sexually is due to genetic recombination. However, this book does not tell me which source of genetic variability, mutations or recombination, produce the largest genetic variations which natural selection operates on.

However, an Anthropology (a science that studies humans within the contexts of biology and culture) textbook states that "Mutations are the most important source of variety
on which natural selection depends and operates."

I am confused. Which is the most important source of variety
on which natural selection depends and operates, mutations or genetic recombination?

Am I correct in stating that, within a population of sexually reproducing organisms, genetic recombination produces more genetic variation compared to mutations and thus is a more important source on of variability on which natural selection operates, whereas in populations of organisms that reproduce asexually mutations are the only source of variability on which natural selection operates?

Thanks.

Cat
King Cobra
King Cobra
Posts: 635
Joined: Thu Feb 14, 2008 7:40 pm

Re: Which has a greater impact of evolution, mutations or genet

Post by Cat » Fri Oct 31, 2014 2:26 am

alpha78 wrote:Am I correct in stating that, within a population of sexually reproducing organisms, genetic recombination produces more genetic variation compared to mutations and thus is a more important source on of variability on which natural selection operates, whereas in populations of organisms that reproduce asexually mutations are the only source of variability on which natural selection operates?


It's hard to answer your question conclusively because it largely depends on the definition for the mutation. When you see something that says that mutations are rare, they most likely meant pathogenic mutations. It such cases benign mutations and silent mutations are considered normal variation resulting in alternative allele. Genetic recombination results in rearrangement of genes leading to progeny having a new and unique combination of genes (except identical twins).

You also have to be careful when you say that "in populations of organisms that reproduce asexually mutations are the only source of variability ". That is not true. First of all, horizontal gene transfer is asexual and very active in bacteria. Second, some organisms are capable of asexual recombination (eg. plants).

Lastly, you are dismissing effect of epigenetics.

Post Reply

Who is online

Users browsing this forum: No registered users and 4 guests