BIOL 1090 Lecture Notes - Lecture 7: Antennapedia, Haploinsufficiency, Null Allele
12 Oct 2016
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Any given gene has many more than two alleles in a population: the most common allele is considered the wild type . Different alleles affect the phenotype in different ways: incomplete dominance. The phenotype of the heterozygote is midway between the phenotypes of the two homozygote. One allele is partially, or incompletely, dominant over the other. Eg: red flowers (ww), bred with white flowers (ww) produces pink offspring (ww) (fig. Half the amount of enzyme, makes half the amount of pigment, meaning the flowers aren"t completely red: codominance. The heterozygote expresses the phenotype of both homozygotes. Both are equally as powerful at expressing their phenotype. Multiple alleles of a single gene with a dominance hierarchy. An allelic series describes the dominance hierarchy of multiple. A single gene may do more than one thing multifunctional alleles (fig. 4. 7) eg of dominant visible allele that is also a recessive lethal (involved in at least two different developmental processes)
