HMB265H1 Lecture Notes - Lecture 6: Wild Type, The Leaves, Base Pair

• School: UTSG
• Department: Human Biology
• Course: HMB265H1
• Professor: Maria Papaconstantinou

Document Summary

Lecture 6 mendelian genetics ii: complementation, allelism, epistasis. Wrinkles in mendel"s laws: gene interactions, complementation/allelism, epistasis. Allelic variation in the world around us: complementation, complementary gene action, and epistasis. Few articles published about 9 years about restoring sight to blind fish. Astyanax mexicanus shows that there are many steps to making an eye, suggesting that different subspecies have mutations in different steps or pathways. Two genes can interact in several ways to determine a single trait. In a dihybrid cross like mendel"s, each type of interaction produces its own signature of phenotypic ratios. Fish live in dark limestone caves in northeast mexico, and blind fish were descendants of a sighted-surface subspecies, and over time, the fish that lived in dark caves lost their sight. Consider: different null (loss-of-function) mutations in the same gene should give rise to the same phenotype. The fish had mutations in different genes, both resulting in blindness.