Mendelian Genetics Definitions 1. Allele - one alternative form of a given allelic pair; tall and dwarf are the alleles for the height of a pea plant; more than two alleles can exist for any specific gene, but only two of them will be found within any individual 2.Allelic pair - the combination of two alleles which comprise the gene pair 3.Homozygote - an individual which contains only one allele at the allelic pair; for example DD is homozygous dominant and dd is homozygous recessive; pure lines are homozygous for the gene of interest 4. Heterozygote - an individual which contains one of each member of the gene pair; for example the Dd heterozygote 5. Genotype - the specific allelic combination for a certain gene or set of genes Mendel's Conclusions: 1. The hereditary determinants are of a particulate nature. These determinants are called genes. 2. Each parent has a gene pair in each cell for each trait studied. The F1 from a cross of two pure lines contains one allele for the dominant phenotype and one for the recessive phenotype. These two alleles comprise the gene pair. 3. One member of the gene pair segregates into a gamete, thus each gamete only carries one member of the gene pair. 4. Gametes unite at random and irrespective of the other gene pairs involved.