Genetics- scientific study of heredity
Fertilization- process in sexual reproduction in which male and female reproductive cells join to form a new cell
Trait- scientific characteristic of an individual
Hybrid- offspring of crosses between parents with different traits
Gene- sequence of DNA that codes for a protein and thus determines a trait; factor that is passed from parents to offspring
Allele- one number of different forms of a gene
Principle of dominance Mendel's second conclusion, which states that some allele are dominant and others are recessive
Segregation- separation of alleles during gamete formation
Gamete- sex cell
Probability-likelihood that a particular event will occur
Homozygous- having two identical alleles for a particular gene
Heterozygous- having two different alleles for a particular gene
Phenotype- physical characteristics of an organism
Genotype- genetic makeup of an organism
Punnett square- diagram that can be used to predict the genotype and phenotype combinations of a genetic cross
Independent assortment- one of Mendel’s principles that states that genes for different traits can segregate independently during the formation of gametes
Incomplete dominance- situation in which one allele is not completely dominant over another allele
Codominance- situation in which the phenotypes produced by both alleles are completely expressed
Multiple alleles- a gene that has more than two alleles
Polygenic trait- trait controlled by two or more genes
Homologous- term used to refer to chromosomes in which one set comes from the male parent and one set comes from the female parent
Diploid- term used to refer to a cell that contains two sets of homologous chromosomes
Haploid- term used to refer to a cell that contains only a single set of genes
Meiosis- process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
Tetrad- structure containing four chromatids that forms during meiosis
Crossing-over- process in which homologous chromosomes exchange portions of their chromatids during meiosis