Lecture 9: Mutations

• mutations - changes in the organism that are heritable and essentially permanent
• Euploidy - changes involving the whole genome on the entire set of chromosome
• Polyploids - are organisms with cells containing three or more sets of chromosomes or genomes
• type of chromosomal mutation: euploidy, aneuploidy, structural changes
• genome (x) - basic chromosome #; complete set of chromosomes or genes from male or female parent
• in polyploid, X is not equal to n (haploid number).
• monoploid - X
• polyploid - 3X to 6X
• autopolyploid - multiplication of one basic genome (identica)
• allopolyploid - genomes are not identical
• monoploid are sterile because the are univalent
• diploid are fertile because they are bivalent
• autotriploid (AAA) 3X forms trivalent
• autotetraploid (AAAA) 4x forms quadrivalent
• allotetraploid (AABB) 4X forms 8 bivalent
• autotetraploid is sterile while allotetraploid is fertile
• allohexaploid (AABBDD) 6X
• types of autotetraploid segregation- random chromosome type and random chromatid type
• random chromosome type - genes are close to centromere
• random chromatid type - genes are far from the centromere
• aneuploidy - addition or subtraction of one or more chromosome