Mendelian & Non-Mendelian Genetics Flashcards | Quizlet

allele

one form or version of a gene

genotype

the two alleles inherited for a particular gene; the genetic make up of a trait; the "genes"

phenotype

an individual's observable traits, such as height, eye color, and blood type; "Physical" traits

dominant

the allele in a genotype that masks the contribution of a second allele at the same locus on a chromosome

recessive

the allele in a genotype that is frequently masked by a second allele at the same locus on a chromosome

homozygous

description of a genotype of an individual who has two of the same allele, whether dominant or recessive

heterozygous

description of a genotype of an individual who has two different alleles, one dominant and the other recessive

Law of Segregation

the principle, originated by Gregor Mendel, stating that during the production of gametes the two copies of each hereditary factor separate so that offspring acquire one factor from each parent

Law of Independent Assortment

the principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors line up independently during gamete production, giving different traits an equal opportunity of occurring together

incomplete dominance

type of dominance that occurs when the phenotype of the heterozygous phenotype is distinct from and often intermediate to the phenotypes of the homozygous phenotypes

codominance

type of dominance that occurs when the contributions of both alleles are visible in the phenotype

polygenic inheritance

type of inheritance that occurs when one characteristic is controlled by two or more genes; often there is a wide range of intermediate phenotypes

monohybrid cross

cross that follows just ONE trait

dihybrid cross

cross that follows TWO traits

test cross

involves the breeding of a phenotypically dominant individual (HH or Hh) with a phenotypically recessive individual (hh), in order to determine the genotype of the former by analyzing proportions of offspring phenotypes

pedigree

the recorded genetics ancestry (family tree of genetics)

Gregor Mendel

an Austrian monk who discovered the basic principles of heredity through experiments in his garden

Punnett square

a diagram that is used to predict an outcome of a particular cross or breeding experiment

Carrier

Heterozygote for a recessive genetic disorder

Epistasis

Phenotypic expression of a gene at one locus alters a gene at a 2nd locus; one gene masks another gene

Pleiotropy

a single gene that has multiple affects on the body such as sickle-cell anemia

Locus

location of a gene on a chromosome

Barr body

A dense body formed from a deactivated X chromosome.

Penetrance

percentage of individuals who show at least some degree of expression of a mutant genotype.

Expressivity

the degree to which a genotype is expressed in an individual; Example genetic disorders can be mild to moderate to severe