Quick Answer: What does it mean if a genotype is homozygous recessive?

What does a homozygous recessive genotype look like?

When a particular gene has identical alleles (versions) of chromosomes inherited from both parents, the gene is homozygous. A homozygous trait is referred to by two capital letters (XX) for a dominant trait, and two lowercase letters (xx) for a recessive trait.

Is TT a homozygous recessive genotype?

When an organism has two of the same alleles for a specific gene, it is homozygous (homo means “same”) for that gene.

Genotype and Phenotype.

Genotype Definition Example
Heterozygous One dominant allele and one recessive allele Tt
Homozygous dominant Two dominant alleles TT
Homozygous recessive Two recessive alleles tt

What do you mean by recessive trait?

A recessive trait is the weak, unexpressed trait of a dichotomous pair of alleles (dominant-recessive) that has no effect in the phenotype of heterozygous individuals.

What is a recessive allele?

Definition. A type of allele that when present on its own will not affect the individual. Two copies of the allele need to be present for the phenotype to be expressed.

Why is the homozygous recessive always used in a Testcross?

Why is a homozygous recessive individual used in a test cross? a. Linked alleles are always homozygous; recessive individuals are more common. … Homozygous individuals will display either the recessive or the dominant phenotype.

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What causes the expression of a recessive trait?


Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele will be expressed, while the effect of the other allele, called recessive, is masked.

Is homozygous dominant a genotype?

A homozygous genotype is one in which both alleles are the same, and an organism with a homozygous genotype is said to be true-breeding or purebred. A homozygous dominant genotype is one in which both alleles are dominant.

What is the term heterozygous mean?

(HEH-teh-roh-ZY-gus JEE-noh-tipe) The presence of two different alleles at a particular gene locus. A heterozygous genotype may include one normal allele and one mutated allele or two different mutated alleles (compound heterozygote).