Thread: Speciation question

Just wondering. Is there a set level of genetic variation between two close species, wherein they can no longer interbreed and produce fertile offspring? Perhaps a certain percentage of their genetic code? Does a higher gene count allow for more variation, before true speciation occurs?

Yes and no..

only like 5% of the dna is usefull (of what we know off)

the rest can be different (like 95%)

it can still be the exact same species with a 95% variation in their genes.

but.. the number of chromosomes does have to be the same.
the lenght and weight of the chromosomes also do have to be the same.
the size of the sperm and the size of the egg also do have to be the same.
animal size is also relevant.

i bet there are other factors, but i don't know them.. for 2 different species to get fertile offspring... i don't know if it is possible, it are none the less 2 different genotypes.

more genes means more variation (ofcourse) and for the rest i don't exactly know what you mean.

dont forget that behvaior needs to be the same, if they are to different they arent attractive toe ach other

a butterfly and a gorilla won't have sex....

Thanks. I've been out of the loop for a while, so I'm trying to get a better understanding of certain things.

Originally Posted by Zwolver

a butterfly and a gorilla won't have sex....

Zoooms into noacks ark
noak: "WHAT THE HELL IS THAT?" and point on a pinguin with elephant head
elephant: "You didnt give and specefic rules of how to mate"
noak: "have u named it?"
elephant: "its george"
noak: "THIS IS SO *BEEP*ING NICE, I`LL JUST THREW THAT*BEEP*ING THING OVER BOARD

Originally Posted by Zwolver

Yes and no..

only like 5% of the dna is usefull (of what we know off)

the rest can be different (like 95%)

it can still be the exact same species with a 95% variation in their genes.

I don't see how that can be possible. The genetic distance between humans and rabbits is about 33%, meaning we are 67% alike when compared with our furry little friends. Indeed, the genetic distance between people (Homo sapiens) and chimpanzees (Pan troglodytes) is between 1-2%, making us 98-99% alike.

We are definately different species.

:? i was saying that the "junk dna" change has no effect (yet to be proven) on the organism.. I bet your numbers mean the amount of genes that do have a function.

indeed, a chimpansee has more resemblances than a rabbit.. but a mouse already comes way closer than a rabbit to a human. still i wonder what scources you have..

Sources:

Page, SL; Chiu, C; Goodman, M. (1999). Molecular phylogeny of Old World monkeys (Cercopithecidae) as inferred from gamma-globin DNA sequences. Molecular Phylogenetics and Evolution, 13(2):348-59

I've another somewhere in my notes, but it eludes me for the moment.

Originally Posted by Partialartist

Just wondering. Is there a set level of genetic variation between two close species, wherein they can no longer interbreed and produce fertile offspring? Perhaps a certain percentage of their genetic code? Does a higher gene count allow for more variation, before true speciation occurs?

Certainly a different chromosome number will limit interbreeding.

A set level of genetic variation? No. That would be totally dependent on the phenotypic and behavioural effects of said genetic variation.

A slight mutation could alter the behaviour dramatically. A huge amount of variation could lie dormant till the right factors appear before speciation is truly occuring.

Originally Posted by spuriousmonkey

Originally Posted by Partialartist

Just wondering. Is there a set level of genetic variation between two close species, wherein they can no longer interbreed and produce fertile offspring? Perhaps a certain percentage of their genetic code? Does a higher gene count allow for more variation, before true speciation occurs?

Certainly a different chromosome number will limit interbreeding.

A set level of genetic variation? No. That would be totally dependent on the phenotypic and behavioural effects of said genetic variation.

A slight mutation could alter the behaviour dramatically. A huge amount of variation could lie dormant till the right factors appear before speciation is truly occuring.

Much obliged.