Variations of Dominance quiz #1 Flashcards
BackVariations of Dominance quiz #1
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BackWhich type of allele is sometimes referred to as a loss-of-function gene?
A recessive allele is often referred to as a loss-of-function gene because it typically results from a gene that does not produce a functional product. The presence of more than two alternative forms of a gene in a population is denoted by the term ______.
Multiple alleles. A(n) dominant gene will exhibit its trait even in the presence of a recessive gene.
Dominant. A trait that exhibits continuous variation (such as human height, for example) is called a(n) polygenic trait.
Polygenic trait. Dominant alleles ______.
Are expressed in the phenotype even when only one copy is present (in both homozygous and heterozygous genotypes). Which definition best describes polygenic traits?
Traits that are controlled by the combined effect of two or more genes. Forms of inheritance that are determined by more than two alleles are referred to as ______.
Multiple alleles. What is the genotype with two different alleles called?
Heterozygous. When an allele has no noticeable effect on an organism, what is it called?
Recessive. A heterozygous genotype codes for a blending of phenotypes in _______ inheritance.
Incomplete dominance. A diploid individual carrying two different alleles at a given gene locus is called ______.
Heterozygous. When one gene has several different forms, resulting in more than two phenotypes, what is this called?
Multiple alleles. The gene for dark eyes is ___ over the gene for blue eyes, which is recessive.
Dominant. If the phenotype reflects the activities of more than one gene, it is called a ______ trait.
Polygenic. A situation where a single individual expresses two different alleles is referred to as ______.
Codominance. What is the term for when there are more than two versions of a gene in a population?
The term is multiple alleles, which refers to the presence of more than two versions of a gene within a population. In a heterozygous individual, which allele is expressed in the phenotype under complete dominance?
In a heterozygous individual, the dominant allele is expressed in the phenotype under complete dominance. How is a dominant allele typically represented in genetic notation?
A dominant allele is typically represented by an uppercase letter, such as 'A'. What do you call a gene that is expressed only in the homozygous state?
A gene that is expressed only in the homozygous state is called a recessive gene or allele. What is a recessive allele?
A recessive allele is an allele that is only expressed in the phenotype when an individual is homozygous for that allele; it is masked by the presence of a dominant allele. What is a dominant allele?
A dominant allele is an allele that is expressed in the phenotype whenever it is present, whether the individual is homozygous or heterozygous for that allele. What type of inheritance pattern is observed in human blood types?
Human blood types exhibit codominance, where both IA and IB alleles are equally expressed if present together. What is it called when one gene overshadows or masks the effect of another gene?
When one gene overshadows or masks the effect of another gene, it is called epistasis. What is the genotype of a person with AB blood type?
A person with AB blood type has the genotype IAIB, meaning they possess both the IA and IB alleles. In which genotype must the dominant gene be present for the dominant trait to show under complete dominance?
Under complete dominance, the dominant trait will show in both the homozygous dominant (AA) and heterozygous (Aa) genotypes. What is incomplete dominance?
Incomplete dominance is a type of inheritance where the phenotype of the heterozygote is intermediate between the phenotypes of the homozygous dominant and homozygous recessive individuals.
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