Sex Chromosomes in Drosophilia melanogaster

[Genecks]

Hey, folks.

 

I'm reviewing the genetics of D. melanogaster, and I have a question inspired by reading a wikipedia article that says this:

 

"It has only four pairs of chromosomes: three autosomes, and one sex chromosome."

 

So, if D. melanogaster has four chromosomes, then how exactly is it going to have a Y and an X chromosome? Are one of the autosomes a Y chromosome? Am I missing or overlooking something here, or is it the idea that the one sex chromosome turns into two chromosomes, which could be XX or XY?

[Mokele]

X and Y are considered a "pair" even though they're different. The same holds true even in birds, where there's simply X or nothing (though, IIRC, XO is female and XX is male).

[Genecks]

Ok, so by "pair," you mean that the sex chromosome is actually a pair of chromosomes. So, in a sense there are two sex chromosomes.

Alright, so doesn't that mean D. melanogaster have 8 chromosomes in total?

 

p.s.

 

In terms of grammar and bionomial nomenclature, should I say D. melanogaster "has" or "have"?

[Mokele]

Ok, so by "pair," you mean that the sex chromosome is actually a pair of chromosomes. So, in a sense there are two sex chromosomes.Alright, so doesn't that mean D. melanogaster have 8 chromosomes in total?

 

Exactly, 3 pairs of autosomal and 1 pair (X and Y) of sex chromosomes.

 

In terms of grammar and bionomial nomenclature, should I say D. melanogaster "has" or "have"?

 

If it's universal to the species (thus the species is being talked about as a singular entity), I think it's "has".

 

D. melanogaster has six autosomal chromosomes.

[marrykonta]

Hi Genecks,

 

Well,Drosophila melanogaster was among the first organisms used for genetic analysis, and today it is one of the most widely-used and genetically best-known of all eukaryotic organisms. All organisms use common genetic systems; therefore, comprehending processes such as transcription and replication in fruit flies helps in understanding these processes in other eukaryotes, including humans.

 

 

Thanks