Faith writes:
You are saying that all individuals of a species have the same number of chromosomes, but didn't someone here say that even within a species some individuals may have a different number?
Yes, someone did say this, and I have no idea why. While it is possible, it's potential for confusion makes it something that shouldn't be mentioned when merely introducing genetic concepts.
What on earth IS a chromosome anyway? It SEEMS like it's just arbitrary segments of DNA that COULD have been simply one long string instead. Is there any point to its being broken up into separate chromosomes?
I agree. I think you're asking a great question: what is the advantage of dividing a cell's DNA into separate pieces we call chromosomes. Presumably it came about because it provides some advantage (error reduction possibly?) Maybe someone out there knows the answer.
Do the different chromosomes have some identifiers that give them particular functions?
It is genes that code for the proteins that produce different functions. Each gene is comprised of a part of the length of the DNA strand that makes up a chromosome. Usually the coiled DNA strand that is a chromosome contains many genes.
it's very interesting that a particular gene is always located on a particular chromosome. Is this true across species in some overall general way, that genes for particular traits that are shared among different species show up on the same chromosome sort of more or less? Meaning for instance eye color which is always the one that comes to mind for some reason, is that gene or set of genes always located on a chromosome that is the same in all species where variations in eye color are a factor?
Checking with Wikipedia, there are many genes that play a role in determination of eye color. Choosing just one as an example,
OCA2, for humans it always resides on chromosome 15, and almost always in the same place on chromosome 15. I wasn't able to find any information about where it is in other species.
Are my questions making any sense?
Rather a lot.
--Percy