What term describes an organism having two identical alleles for a gene?

What term describes an organism having two identical alleles for a gene?

• A. Heterozygous
• B. Homozygous
• C. Hemizygous
• D. Polyploid

Answer: (B)

Two identical alleles for a gene indicate homozygosity. In diploid organisms, each gene has two alleles, one from each parent. When these two alleles are the same, the genotype is homozygous (for example, TT or tt). If the two alleles are different, the genotype is heterozygous (like Tt). Hemizygous refers to having only one allele for a gene in a diploid context (as with genes on the X chromosome in males for many traits), and polyploid means having more than two complete sets of chromosomes. So the term for two identical alleles is homozygous.

Two identical alleles for a gene indicate homozygosity. In diploid organisms, each gene has two alleles, one from each parent. When these two alleles are the same, the genotype is homozygous (for example, TT or tt). If the two alleles are different, the genotype is heterozygous (like Tt). Hemizygous refers to having only one allele for a gene in a diploid context (as with genes on the X chromosome in males for many traits), and polyploid means having more than two complete sets of chromosomes. So the term for two identical alleles is homozygous.