Unit 9 Genetics Vocabulary-Biology

allele

any of the alternative forms of a gene that occurs at a specific place on a chromosome

cross

mating of two organisms

dihybrid cross

cross, or mating, between organisms involving two pairs of contrasting traits.

dominant

allele that is expressed when two different alleles are present in an organism's genotype.

gene

specific region of DNA that codes for a particular protein.

genome

all of an organism's genetic material.

genotype

collection of all of an organism's genetic information that codes for traits.

heterozygous

characteristic of having two different alleles that appear at the same location on sister chromatids.

homozygous

characteristic of having two of the same alleles at the same location on sister chromatids.

monohybrid cross

cross, or mating, between organisms that involves only one pair of contrasting traits.

phenotype

collection of all of an organism's physical characteristics.

punnett square

model for predicting all possible genotypes resulting from a cross, or mating.

purebred

type of organism whose ancestors are genetically uniform.

recessive

allele that is not expressed unless two copies are present in an organism's genotype.

test cross

cross between an organism with an unknown genotype and an organism with a recessive phenotype.

trait

characteristic that is inherited.