BIOL 2107 Lecture Notes - Lecture 3: Heterogametic Sex, Cleavage Furrow, S Phase

• School: Carleton University
• Department: Biology
• Course: BIOL 2107
• Professor: Bahram Samanfar

Document Summary

Two genes can interact to determine one trait. Observing the f2 ratios below is diagnostic of the type of gene interactions. These f2 ratios occur only in dihybrid crosses where there is complete dominance. Heterogeneous traits: have the same phenotype but are caused by mutations in different genes; i. e. deafness in humans can be caused by mutations in roughly 50 different genes. Complementation testing: used to determine if a particular phenotype arises from mutations in the same or separate genes; can be applied only with recessive, not dominant, phenotypes. Interaction of two incompletely dominant genes can produce nine phenotypes. A and b: allele a is incompletely dominant to allele a, allele b is incompletely dominant to allele b. For each gene, two alleles generate three phenotypes. Family pedigrees help unravel the genetic basis of ocular-cutaneous albinism (oca). The same genotype does not always produce the same phenotype.