What term describes having the same allele at the loci for a gene on both members of a pair of homologous chromosomes?

What term describes having the same allele at the loci for a gene on both members of a pair of homologous chromosomes?

• A. Homozygous
• B. Heterozygous
• C. Locus
• D. Zygote

Answer: (A)

Having the same allele on both copies of a chromosome pair for a given gene means the genotype is homozygous for that gene. Each gene sits at a specific location on the chromosome called a locus, and an allele is a variant form of that gene. When both homologous chromosomes carry the identical allele at that locus, you have a homozygous genotype, whether the allele is the dominant form or the recessive form. If the two alleles are different, the genotype is heterozygous. The other terms aren’t about this state: a locus is the gene’s position, and a zygote is a fertilized egg.

Having the same allele on both copies of a chromosome pair for a given gene means the genotype is homozygous for that gene. Each gene sits at a specific location on the chromosome called a locus, and an allele is a variant form of that gene. When both homologous chromosomes carry the identical allele at that locus, you have a homozygous genotype, whether the allele is the dominant form or the recessive form. If the two alleles are different, the genotype is heterozygous. The other terms aren’t about this state: a locus is the gene’s position, and a zygote is a fertilized egg.