Do homologous chromosomes have the same number of genes? Do they have identical genes? Explain.?

Question

Do homologous chromosomes have the same number of genes? Do they have identical genes? Explain.?

Answer 1

> Do homologous chromosomes have the same number of genes?

Ideally, yes they do.

> Do they have identical genes?

No.  The two chromosomes will have different alleles in heterozygous individuals, for particular traits (or gene products).

Answer 2

Homologous chromosomes have the same number of genes but they may be the same or different forms (= alleles) depending on what they received from each parent when the two sets of chromosomes combined at fertilisation.

EG.Chromosome 7 spans more than 158 million base pairs (the building material of DNA) and represents between 5 and 5.5 percent of the total DNA in cells.  The estimated number of genes varies. Chromosome 7 likely contains between 1,000 and 1,400 genes.

The cystic fibrosis gene (CFTR) is on chromosome 7 but this allele is not necessarily, and unlikely to be, on both of the two homologous chromosomes from each parent. So each parent will have either the CFTR allele or the normal allele.

http://www.ornl.gov/sci/techresources/Hu...