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Chapter 6 Part 2
Mendel
Term | Definition |
---|---|
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 |
law of segregation | Mendel's first law, stating that (1) organisms inherit two copies of genes, one from each parent, and (2) organisms donate only one copy of each gene in their gametes because the genes separate during gamete formation |
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 | characteristics of having two of the same alleles at the same locus of sister chromatids |
heterozygous | characteristics 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 |
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 squares | 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 |
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 I |
genetic linkage | tendency for genes located close together on the same chromosome to be inherited together |