Hi, I am struggling with a phrase in a text book I am reading at a section discussing gene duplication (note this is not a question for amateurs). The phrase reads "the Genomes of many jawed vertebrates appear to have four diploid sets of many major genes." I have read this phrase several times, and for what ever reason it just isn't sinking in what it means? I mean I understand that the chromosomes of almost all living things are diploid in one way or another, but what does "four diploid sets of many major genes mean in reality? Would anyone care to expand on this?

Edited March 3, 201213 yr by raid517

of almost all living things are diploid in one way or another

Minor comment on that part, depending on how you count probably the minority are actual diploid. Regarding your question, I am not completely sure whether the statement is true, especially considering the vagueness of it. I.e. major gene can be used in any number of contexts. That being said I assume the author tries to say that in the ancestor of jawed vertebrates two duplications of these genes have happened.

OK, well you have my attention. Would you care to expand on your own comment on how 'the minority of organisms are diploid'?

 

How would you count this to infer this outcome?

 

I think you are correct and the authors wording is simply vague, and that what he means is that there are 4 copies of each of several important genes present in many of the jawed vertebrates. It is just a strange way to word it.

Think for instance about prokaryotes.

Think for instance about prokaryotes.

 

Well indeed, good point, there's an awful lot of them. Asexual reproduction/ conjugation etc. But aren't the chromosomes of the prokaryotes diploid? They may indeed not produce haploid gametes like the eukaryotes, but although they reproduce via binary fission, aren't their chromosomes still diploid?

Nope. Prokaryotes are all haploid. Many have only one chromsome, though some have several. These carry totally different set of genes, however. The chromsome structure is also totally different from eukaryotes. You may want to look up the differences. It is quite interesting (and very important basic knowledge, too).

Nope. Prokaryotes are all haploid. Many have only one chromsome, though some have several. These carry totally different set of genes, however. The chromsome structure is also totally different from eukaryotes. You may want to look up the differences. It is quite interesting (and very important basic knowledge, too).

 

Do you have a link explaining this difference in more detail? It would be useful to just have a place marker here I could refer back to.