Mutation II

Mutation --- Chromosomal Level ??? Crossing over Deletions (deficiencies) Terminal Intercalary IF small, MIGHT not have a major effect. Cri-du-chat Syndrome (cat cry syndrome) deletion in short arm of chromosome 5

Duplications Section present two or more times in a chromosome If small might not have a negative effect. Large duplication usually has a negative effect. WHY???? Evolutionary significance of duplicated material

Translocations Between non-homologous chromosomes Reciprocal Non-reciprocal We will “assume” no position effect In translocation heterozygotes fertility is reduced Fertility (F) = 1 / 2n-1 n = number of chromosome pairs repatterned through translocation

Translocations Fertility reduction only happens in the heterozygotes! Gives rise to cross and ring configurations during meiosis Evolutionary importance --- partial isolation (reduced fertility in offspring of matings between different strains) Our Example: a reciprocal translocation