Chromosome Mutations in Meiosis April 23, 2019

Mutations

Mutations Sometimes pieces of chromosomes are lost, duplicated or moved within a chromosome or to another chromosome during meiosis

Mutations Sometimes pieces of chromosomes are lost, duplicated or moved within a chromosome or to another chromosome during meiosis These changes are called mutations

Mutations Sometimes pieces of chromosomes are lost, duplicated or moved within a chromosome or to another chromosome during meiosis These changes are called mutations These mutations affect many genes in the chromosome and change the proteins made by those genes

Some types of chromosome mutations

Mutations

Mutations Mutations also occur when cells are exposed to mutagens such as radiation or chemicals

Mutations Mutations also occur when cells are exposed to mutagens such as radiation or chemicals E.g. some fruit flies exposed to mutagens have legs growing where antennae should be

Whole Chromosome Mutations

Whole Chromosome Mutations Whole chromosome mutations can occur in meiosis I (when homologous chromosomes fail to separate) or in meiosis II (when sister chromatids fail to separate)

Whole Chromosome Mutations Whole chromosome mutations can occur in meiosis I (when homologous chromosomes fail to separate) or in meiosis II (when sister chromatids fail to separate) The result is that one gamete has 2 copies of the same chromosome and the other will have no copy of that chromosome

Whole Chromosome Mutations

Whole Chromosome Mutations

Whole Chromosome Mutations Usually whole chromosome errors are prevented from being passed along because the offspring either fails to develop or does not live to reach reproductive age and adulthood

Whole Chromosome Mutations Usually whole chromosome errors are prevented from being passed along because the offspring either fails to develop or does not live to reach reproductive age and adulthood Some chromosome mutations result in genetic disorders or syndromes such as Down syndrome

Karyotype

Karyotype A picture of an individual’s chromosomes, arranged by size

Karyotype A picture of an individual’s chromosomes, arranged by size

Karyotype

Karyotype Karyotypes can show genetic disorders

Karyotype Karyotypes can show genetic disorders The karyotype of a person with Down syndrome:

Karyotype Karyotypes can show genetic disorders The karyotype of a person with Down syndrome: A person with Down syndrome has an extra 21st chromosome

Karyotype Karyotypes can show genetic disorders The karyotype of a person with Down syndrome: A person with Down syndrome has an extra 21st chromosome This individual is a male because they have a Y chromosome

Karyotype Karyotypes can show genetic disorders The karyotype of a person with Down syndrome: A person with Down syndrome has an extra 21st chromosome This individual is a male because they have a Y chromosome (Females have 2 X chromosomes)

Edwards Syndrome

Turner Syndrome

Textbook Questions Page 203 #1-18