BIOL239 Lecture Notes - Y Chromosome, Chromosome, Halothane
20 May 2013
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Document Summary
Genes can also determine differences between sexes: sex-limited traits. Affect a structure or process that is found in one sex but not the other. E. g. , bright plumage in male birds, milk production, horns/antlers: sex-influenced traits show up in both sexes but their expression may differ between the two sexes. Due to genes on the x or y chromosome. E. g. , hemophilia and color blindness: 007 = b_ vs b+b+(hair) Premature loss of hair from top of head, but not sides. Begins in late 20s in heterozygous men, but heterozygous women show no effect in homozygous men and women, baldness results in both, but much earlierin men influenced by sex hormones. Environment: factors such as temperature, light, and altitude can affect the phenotypic expression of a genotype, the environment can affect the phenotypic expression of a genotype, himalayan coat pattern in cats, rabbits, conditional lethality. Occurs with a particular type of allele which is lethal under only certain conditions.
