17 terms

Biology Ch. 6--sec.4-6

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gene
specific region of DNA that codes for a particular protein
allele
any of the alternate forms of a gene that occurs at a specific place on a chromosome
homozygous
characteristic of having 2 of the same alleles that appear at the same locus of sister chromotid
heterozygous
characteristic of having 2 different alleles that appear at the same locus of sister chromotid
genome
all of an organisms genetic material
genotype
collection of all of an organisms genetic info that codes for traits
phenotype
collection of all of an organisms physical characteristics
dominant
allele that is expressed when 2 different alleles are present in an organisms genotype
recessive
allele that is not expressed unless 2 copies are present in an organisms genotype
Punnett square
model for predicting all possible genotypes resulting from a cross, or mating
monohybrid cross
cross, or mating, between organisms that involves only 1 pair of contrasting traits
testcross
cross between an organism with an unknown genotype and an organism with a recessive genotype
dihybrid cross
cross, or mating, between organisms involving 2 pairs of contrasting traits
law of independent assortment
Mendel's second law, stating that allele pairs separate from one another during gamete formation
probability
likelihood that a particular event will happen
crossing over
exchange of chromosome segments between homologous chromosomes during meiosis
genetic linkage
tendency for genes located close together on the same chromosome