Mendellian Genetics Vocab - CORE Acc. Biology 9

from the handout given in class

trait

characteristic that is inherited

genetics

study of the heredity patterns and variation of organisms

purebred

type of organism whose ancestors are genetically uniform

cross

mating of two organisms

gene

specific region of DNA that codes for a particular protein

allele

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

homozygous

characteristic of having two of the same alleles at the same locus of sister chromatids

heterozygous

characteristic of having two different alleles that appear at the same locus of sister chromatids

genome

all of an organism’s genetic material

genotype

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

phenotype

collection of all of an organism’s physical characteristics

dominant

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

recessive

allele that is not expressed unless two copies are present in an organism’s 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 one pair of contrasting traits

testcross

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

dihybrid cross

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

probability

likelihood that a particular event will happen

crossing over

exchange of chromosome segments between homologous chromosomes during meiosis I

linkage map

diagram that shows the relative locations of genes on a chromosome