Chromosomal Mutations Honors Biology Review Gene Mutations Micromutations
Chromosomal Mutations Honors Biology
Review: Gene Mutations • “Micromutations” • Small changes to DNA – One or several bases – Change can be positive, negative, or neutral • Can be passed to offspring if in gametes
Chromosomal Mutations • “Macromutations” • Large changes to DNA segments/chromosomes – Can be structural (part of chromosome) – Can be a change in chromosome number (whole chromosome) • Usually a meiosis error – So not always a mutation passed from parents to offspring • Diagnosable through karyotyping or gene testing
STRUCTURAL MUTATIONS
Deletion • A portion of a chromosome is missing • Ex: cri du chat syndrome
Duplication • A portion of a chromosome is duplicated • Ex: Charcot–Marie–Tooth disease
Inversion • A chromosome undergoes breakage and rearrangement within itself • Ex: chromosome 9 inversion leads to infertility in 1 -3% of the general population (improper sperm formation in men, spontaneous miscarriage in females)
Translocation • A portion of one chromosome is transferred to another chromosome • Ex: chromosome 9 & 22 – chronic myelogenous leukemia
NUMBER MUTATIONS
Monosomy • Missing one chromosome from a pair/pairs • Ex: Turner Syndrome
Trisomy • Three copies of a chromosome • Ex: Down Syndrome
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