Biology Unit 07 - Applied Genetics

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alleles
different forms of a gene
carrier
person who has one recessive allele for a trait, but does not have the trait
co-dominance
both alleles for a gene are fully expressed in the heterozygous condition (such as strips or patches of two colors)
cross-fertilization
fusion of sperm and egg derived from two different individuals
dihybrid cross
cross applied to two characteristics with four alleles
dominant allele
trait that is expressed in a heterozygous genotype
F1 generation
offspring of the P generation; first filial generation
F2 generation
offspring of the F1 generation; second filial generation
genetics
branch of biology that studies heredity and variation in organisms
genotype
organism's genetic makeup, or allele combinations
heterozygous
having two different alleles for a trait; hybrid
homozygous
having two identical alleles for a trait; pure or true-breeding
hybrid
offspring of crosses between parents with different traits
inbreeding
continued breeding of individuals with similar characteristics
incomplete dominance
creates a blended phenotype; one allele is not completely dominant over the other
monohybrid cross
cross applied to a single characteristic with two alleles
P generation
parental generation, the first two individuals that mate in a genetic cross
pedigree
family tree representing the occurrence or heritable traits in parents and offspring across generations
phenotype
physical traits that appear in an individual as a result of its gentic make up.
Punnett square
chart that shows all the possible combinations of alleles that can result from a genetic cross
recessive allele
trait that is hidden in a heterozygous genotype
self-fertilization
fusion of sperm and egg produced by the same individual organism
sex-linked gene
gene located on the X or Y chromosome
testcross
real life cross between an organism whose genotype for a dominant trait is unknown and an organism that is homozygous recessive for that trait