BIOLOGY 1A03 Lecture Notes - Lecture 18: Uracil, Hemoglobin, Lysine

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Kim Dej

Document Summary

Theme 4 applied lecture: mutations and gene evolution. As they duplicate this can lead to families of related genes. Since they come from the same progenitor gene, they often have related biochemical functions. Gene families can expand and contract over evolutionary time scales. The oxygen carrying hemoglobin (hb) contains two kinds of polypeptides, alpha- globin and beta-globin. Humans express different versions of alpha and beta genes as they develop from embryo to fetus and adult. These genes evolved from mutation of an ancestral globin gene. Fetal form used for about 6 weeks before birth. Adult used from about birth onwards dominate after 6 week after birth. Fetal hb has a higher affinity for oxygen. Sequence at beginning of the gene, exon 1. Reduced oxygen supply throughout body=cell death, tissue degeneration, pain, death. Physiological symptoms similar to sickle cell anemia; see developmental delays in children.