LSCI 204 Lecture Notes - Lecture 7: Heredity, Carotenoid, Wild Type
8 Feb 2018
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Document Summary
Chapter 4: extensions and modifications of basic principles. Additional factors at a single locus can affect the results of genetic crosses. Lethal alleles can be dominant: homozygotes and heterozygotes = death. Genes at the same locus two versions of the same gene; each version of the same gene is defined as allele. The type of dominance exhibited by a trait depends on how the phenotype of the heterozygote relates to the phenotypes of the homozygotes. Complete dominance: phenotype of the heterozygote is the same as the phenotype of one of the homozygotes. Incomplete dominance: phenotype of heterozygote is intermediate (falls within the range) between the phenotypes of the two homozygotes. Codominance: phenotype pf the heterozygote includes the phenotypes of both homozygotes. Penetrance: the percentage of individuals having a particular genotype that express the expected phenotype. Expressivity: the degree to which a character is expressed.
