Genetics Exam 1 Flashcards
Allele
One of the different forms of a gene that can exist at a single locus
Wild Type
The genotype or phenotype that is found in nature or in the standard laboratory stock for a given organism
Dominant
The phenotype shown by a heterozygote
Recessive Allele
An allele whose phenotypic effect is not expressed in a heterozygote
Phenotype
The form taken by some character (or group of characters) in a specific individual. The detectable outward manifestations of a specific genotype
Penetrance
The proportion of individuals with a specific genotype that manifest that genotype at the phenotype level.
Genotype
The Allie composition of an individual or of a cell— either of the entire genome or, more commonly, of a certain gene or set of genes
Heterozygous Gene Pair
A gene pair having different alleles in the two chromosome sets of the diploid individual
Complementation
A test for determining whether two mutations are in different genes (they compliment) or the same gene (they do not complement)
Crossing over
The exchange of corresponding chromosome parts between homologous by breakage and reunion
Expressivity
The degree to which a particular genotype is expressed in the phenotype
F1 Generation
The first filial generation produced by crossing two parental lines
F2 generation
The second filial generation produced b y selfing or intercrossing the F1 generation
Genetic Map Unit (M.U.)
A distance on the chromosome map corresponding to 1 percent recombinant frequency
Linked
The situation in which two genes are on the same chromosome as deducted y recombinant frequencies less than 50%
Maternal inheritance
A type of uniparental inheritance in which all progeny have the genotype and phenotype of the parent acting as the female
Molecular marker
A site of DNA heterozygosity, not necessarily associated with phenotypic variation, used as a tag for a particular chromosomal locus
Monohybrid cross
A cross between two individuals identically heterozygous at one gene pair- for example A/a x A/a
Penetrance
The proportion of individuals with a specific genotype that manifest that genotype at the phenotype level
Physical map
The ordered and oriented map of cloned DNA fragments on the genome
Recombination frequency
The proportion or percentage of recombinant cells or individuals
Recombination map
A chromosome map in which the positions of loci shown are based on recombinant frequencies
Sex chromosome
A chromosome whose presence or absence is correlated with the sex of the bearer; a chromosome that plays a role in sex determination
Sex linkage
The location of a gene on a sex chromosome
Simple sequence length polymorphism
The existence in the population of individuals showing different members of copies of a short simple DNA sequence at one chromosomal locus
Single nucleotide polymorphism
A nucleotide-pair difference at a given location in the genomes of two or more naturally occurring individuals
Test cross
A cross of an individual organism of unknown genotype or a heterozygote (or multiple heterozygote) with a tester
Three-point testcross
A test cross in which one parent has three heterozygous gene pairs
X linkage
The inheritance pattern of genes found on the X chromosome but not on the Y chromosome
Y linkage
The inheritance pattern of genes found on the Y chromosome but not on the X chromosome (rare)
