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Mendelian Genetics

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MENDELIAN GENETICS DEFINITION OF TERMS * Genetics – the study of heredity and variation * Heredity – the transmission of traits from one generation to another, from parents to offspring; the protoplasmic continuity between parents and offspring * Variation – any difference existing between individuals of the same species * Chromosome – rod-shaped body in the nucleus of eukaryotes and prokaryotes that contains the hereditary units or genes seen particularly during cell division * Gene – the unit or heredity occupying a particular location on the chromosome and passed on to offspring * Locus – the location of a gene on a chromosome * Diploid – the 2N number of chromosomes; twice the number of chromosomes found in gametes * Haploid – the N number of chromosomes; half the diploid number; the number characteristic of gametes that contain only one set of chromosomes * F1 generation – first filial generation; the first-generation offspring of a genetic cross that has at least two generation * F2 generation – second filial generation; the second-generation offspring of a genetic cross * Homozygous – a pair of similar of like genes for any one character * Heterozygous – a pair of contrasting traits of two kinds of genes * Genotype – the particular genes of an individual that determine a specific trait * Phenotype – the outward appearance of an organism, caused by genetic and environmental influences * Allele – a pair of similar or contrasting character; one of two or more alternative states of gene * Dominant allele – hereditary factor that expresses itself when the genotype is heterozygous * Recessive allele – hereditary factor that expresses itself only when the genotype is homozygous * Hybrid – the offspring of two parents that differ in one or more heritable character *

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