cmb chapter 12

These flashcards cover significant vocabulary and concepts related to the basic principles of heredity as discussed in the lecture.

Phenotype

The observable physical or biochemical characteristics of an organism as determined by both genetic makeup and environmental influences.

Genotype

The genetic constitution of an individual, referring specifically to alleles at specific gene loci.

Allele

An alternative form of a gene that arises by mutation and is found at the same place on a chromosome.

Homozygous

A genotype consisting of two identical alleles for a given gene.

Heterozygous

A genotype consisting of two different alleles for a given gene.

Dominant allele

An allele that masks the effect of the recessive allele in a heterozygous genotype.

Recessive allele

An allele that is masked by the presence of a dominant allele and is only expressed in a homozygous genotype.

Locus

The specific physical location of a gene or genetic marker on a chromosome.

Segregation

The principle stating that during meiosis, alleles for each locus segregate so that each gamete carries only one allele for each gene.

Independent assortment

The principle that alleles of different genes assort independently of one another during gamete formation.

Monohybrid cross

A genetic cross between two individuals who differ in a single trait.

Dihybrid cross

A genetic cross between two individuals who differ in two traits.

Test cross

A genetic cross between an individual with an unknown genotype and a homozygous recessive individual.

Incomplete dominance

A form of inheritance in which the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes.

Codominance

A form of inheritance in which both alleles in a heterozygote are fully expressed, resulting in a phenotype that is neither dominant nor recessive.

Pleiotropy

A situation where one gene influences multiple phenotypic traits.

Epistasis

A genetic interaction where one gene’s expression is suppressed by another gene.

Polygenic inheritance

A form of inheritance in which multiple genes contribute to a single trait.

Norm of reaction

The range of phenotypic possibilities from a single genotype under different environmental conditions.