Are non-sex chromosomes considered homologous?

[Agent M27]

Are all chromosomes, aside from the X and Y chromosomes, homologous? This is what my book is implying, however I cannot find a clear, definitive, yes or no. If this is the case I guess my next question would be; how is this possible? I know that homologues have the same length, gene location, and centromere position. However, if I am inheriting genes from one parent, who is unrelated to my other parent, how can the chromosomes I inherited be homologous? Thanks in advance.

Joe

 

[mishrashubham]

Are all chromosomes, aside from the X and Y chromosomes, homologous?

Yes they are.

How is this possible? I know that homologues have the same length, gene location, and centromere position. However, if I am inheriting genes from one parent, who is unrelated to my other parent, how can the chromosomes I inherited be homologous?

Well you answered your question yourself! Pairs of chromosomes which have the same length, the same genes at their corresponding locations (loci to be precise), and centromere position, are called homologous chromosomes.

I understand what you are trying to imply, that the chromosomes inherited from the parents are different. But they are only different with respect to the alleles of the genes which are present in them, not the genes themselves. A pair of homologous chromosomes will have the same gene at the same place though they may be two different alleles of the same gene.

Also relatedness does not matter. In fact it is beneficial for the child if the parents are not closely related, but that's another story.

 

[Agent M27]

Thanks a lot mishrashubham, I think I got it now. Since there must be a gene for eyes, hair, etc. both parents, in general, posses all of these genes, it is the alleles which are different. If I understand correctly, when the chromosomes from each parent join, they are of the same architecture, except one may have the allele for brown eyes while the other chromosome might have the gene for green eyes, but the genes themselves are the same. Thanks again.

Joe