If two different alleles are present for a gene, the genotype is described as what?

If two different alleles are present for a gene, the genotype is described as what?

• A. Homozygous
• B. Heterozygous
• C. Dominant
• D. Recessive

Answer: (B)

Having two different alleles for a gene means the genotype is heterozygous. In diploid organisms, genes come in pairs, one on each chromosome. If the pair are the same, the genotype is homozygous; if they are different, it’s heterozygous. The terms dominant and recessive describe how the trait shows up in the organism (phenotype), not the fact that the two alleles are different. So in a heterozygous individual, often one allele is dominant and determines the phenotype, while the other is recessive, but the genotype itself remains two different alleles.

Having two different alleles for a gene means the genotype is heterozygous. In diploid organisms, genes come in pairs, one on each chromosome. If the pair are the same, the genotype is homozygous; if they are different, it’s heterozygous. The terms dominant and recessive describe how the trait shows up in the organism (phenotype), not the fact that the two alleles are different. So in a heterozygous individual, often one allele is dominant and determines the phenotype, while the other is recessive, but the genotype itself remains two different alleles.