BIOL 2153 Chapter : Chapter 4 Review Exam 2

• School: LSU
• Department: Biological Sciences
• Course: BIOL 2153
• Professor: All

Document Summary

Mutant alleles can be: gain-of-function, in which the gene product acquires a new function or express increased wild type activity, loss-of-function, in which there is a significant decrease or complete loss of functional gene product. Loss-of-function mutations that produce no functional gene product is called a null mutation, or amorphic mutation; often these are lethal when homozygous. Loss-of-function mutations that result in a partial loss of function are called leaky mutation or hypomorphic mututations; the severity of the phenotype of these depends on the level of activity of the leaky mutation. Multi-meric proteins, composed of two or more polypeptides that join together to form a functional protein are particularly subject to dominant negative mutations. Hypermorphic mutations produce more gene activity than normal. Neomorphic mutations acquire novel gene activities not found in the wild type. General (non-epistatic) dominant relationship: complete dominance, b>b; in this case, there is detectable expression of both alleles in the heterozygotes, incomplete dominance, blending theory red,white pink.