Unit 7 Flashcards
Alleles
Alternative versions of a gene that produce distinguishable phenotypic events
Carrier
In genetics, an individual who is heterozygous at a given genetic locus, with one normal allele and one potentially harmless recessive allele. The heterozygote is phenotypically normal for the character determined by the gene but can pass on the harmful allele to offspring
Character
An observable heritable feature
Codominance
The situation in which the phenotypes of both alleles are exhibited in the heterozygote
Complete dominance
The situation in which the phenotypes of the heterozygote and dominant homozygote are indistinguishable
Dihybrid
An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of AABB and aabb produce a dihybrid of AaBb
Dominant allele
An allele that is fully expressed in the phenotype of a heterozygote
Epistasis
A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited
F1 generation
The first filial, or hybrid, offspring in a series of genetic crosses
F2 generation
Offspring resulting from interbreeding of the hybrid F1 generation
Genotype
The genetic makeup, or set of alleles, of an organism
Heterozygous
Having two different alleles for a given gene
Homozygous
Having two identical alleles for a given gene
Hybridization
In genetics, the mating, or crossing, of two true-breeding varieties
Incomplete dominance
The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele
Law of Independent Assortment
Mendel’s second law, stating that each pair of alleles segregates independently during gamete formation; applies when genes for two characters are located on different pairs of homologous chromosomes
Law of segregation
Mendel’s first law, stating that each allele in a pair separates into a different gamete during gamete formation
Monohybrid
An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotype AA and aa produce a monohybrid of genotype Aa.
P generation
The parent individuals from which offspring are derived in studies of inheritance; P stands for “parental”
Phenotype
The physical and physiological traits of an organism, which are determined by its genetic makeup
Pleiotropy
The ability of a single gene to have multiple effects
Polygenic inheritance
An additive effect of two or more gene loci on a single phenotypic character
Recessive allele
An allele whose phenotypic effect is not observed in a heterozygote
Trait
An detectable variation in genetic character
True-breeding
Referring to plants that produce offspring of the same variety when they self-pollinate
