MBG 2040 Lecture Notes - Lecture 6: Spindle Apparatus, Colchicine, S Phase

• School: University of Guelph
• Department: Molecular Biology and Genetics
• Course: MBG 2040
• Professor: Uniacke

Document Summary

Many plants and most animal species are diploid. Ants, bees and wasps have monoploid males: a) monoploidy: only one set of chromosomes. Polyploidy: more than two sets of chromosomes: b) polyploidy: more than the normal number of sets of chromosomes. Polyploidy: plant kingdom: 30-35% of flowing plants are polyploids, animal kingdom: polyploidy is rare. Autopolyploids: the chromosome sets are all identical, all chromosomes are derived from the same species, autopolyploids usually have, more vegetative growth (larger cells, thicker leaves, bigger flowers, larger plants, bigger fruits, less seed production. This can happen spontaneously or by using the chemical colchicine an inhibitor of mitotic spindle formation. Problems with polyploidy: many polyploids are sterile due to problems with paring and separation of homogenous chromosomes in meiosis. Because they are homologous the three can all join in as a trivalent (hard to pull apart because extra interactions with 3 chromosomes: the number of chromosomes in a gamete from a banana cultivar can vary.