A homozygous dominant allele combination contains two dominant alleles and expresses the dominant phenotype (expressed physical trait). A homozygous recessive allele combination contains two recessive alleles and expresses the recessive phenotype.
Can two recessive alleles be homozygous?
Some alleles are dominant, while others are recessive. The dominant allele is expressed more strongly, so it masks the recessive allele. However, in a homozygous genotype, this interaction doesn’t occur. You either have two dominant alleles (homozygous dominant) or two recessive alleles (homozygous recessive).
What is a recessive allele pair?
Genes come in pairs. One gene in each pair comes from the mother, and the other gene comes from the father. Recessive inheritance means both genes in a pair must be abnormal to cause disease.
What is homozygous allele?
(HOH-moh-ZY-gus JEE-noh-tipe) The presence of two identical alleles at a particular gene locus. A homozygous genotype may include two normal alleles or two alleles that have the same variant.
What is a heterozygous allele pair?
Getty Images. Heterozygous is a term used in genetics to describe when two variations of a gene (known as alleles) are paired at the same location (locus) on a chromosome. By contrast, homozygous is when there are two copies of the same allele at the same locus.
Is recessive homozygous or heterozygous?
An organism with one dominant allele and one recessive allele is said to have a heterozygous genotype. In our example, this genotype is written Bb. Finally, the genotype of an organism with two recessive alleles is called homozygous recessive.
Which allele combination represents a homozygous recessive individual?
Homozygous alleles may be dominant or recessive. A homozygous dominant allele combination contains two dominant alleles and expresses the dominant phenotype (expressed physical trait). A homozygous recessive allele combination contains two recessive alleles and expresses the recessive phenotype.
What are homozygous and heterozygous alleles?
Homozygous: You inherit the same version of the gene from each parent, so you have two matching genes. Heterozygous: You inherit a different version of a gene from each parent.
What is the difference between homozygous dominant heterozygous and homozygous recessive?
An organism can be homozygous dominant, if it carries two copies of the same dominant allele, or homozygous recessive, if it carries two copies of the same recessive allele. Heterozygous means that an organism has two different alleles of a gene. … People with CF are homozygous recessive.
What is the difference between homozygous and heterozygous?
Heterozygous refers to having inherited different forms of a particular gene from each parent. A heterozygous genotype stands in contrast to a homozygous genotype, where an individual inherits identical forms of a particular gene from each parent.
What is a homozygous pair of chromosomes?
Supplement. The term homozygous is used to describe that which has the same or identical alleles for a particular trait located at similar loci on paired chromosomes (i.e. homologous chromosomes). In a diploid organism, there are two sets of chromosomes.
When is a recessive trait expressed?
Refers to a trait that is expressed only when genotype is homozygous; a trait that tends to be masked by other inherited traits, yet persists in a population among heterozygous genotypes.
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 an example of heterozygous combination?
If the two versions are different, you have a heterozygous genotype for that gene. For example, being heterozygous for hair color could mean you have one allele for red hair and one allele for brown hair. The relationship between the two alleles affects which traits are expressed.