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Number Mutations

Number Mutations. Chromosomal Disorders. Meiosis isn’t always perfect . Sometimes humans wind up with extra or missing chromosomes Chromosomes fail to separate properly in meiosis (nondisjunction (Not coming apart) occurs leading to abnormal number of chromosomes)

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Number Mutations

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  1. Number Mutations

  2. Chromosomal Disorders • Meiosis isn’t always perfect. • Sometimes humans wind up with extra or missing chromosomes • Chromosomes fail to separate properly in meiosis (nondisjunction (Not coming apart) occurs leading to abnormal number of chromosomes) • Humans can still survive and have an adequate life expectancy

  3. Large Scale Mutations • Non-disjunction: • Failure of chromosomes to separate during meiosis • Monosomy: • Missing one chromosome from a pair/pairs • Trisomy: • Three copies of a chromosome (Tri means 3) • Polyploidy: • The resulting zygote contains one or more extra or missing chromosomes • Aneuploidy: • The resulting zygote contains an extra or missing chromosome

  4. Trisomy 21 • Down’s Syndrome • Mental impairment • Upward-slanted eyes • Slightly flattened facial features • Tend to be cheerful

  5. Trisomy 18 • Edward’s Syndrome • Most die before birth; those born die within 2 months • Heart abnormalities • Difficulty breathing • Small in size

  6. Trisomy 13 • Patau Syndrome • 80% of children die within the 1 year • Intellectual disability • Structural eye defects • Extra digits • Cleft Plate

  7. Female Chromosome Abnormalities • Turner Syndrome • Have single X but no other sex chromosome (XO) • Tend to be short • Do not reach sexual maturity • Hormone injections help

  8. Male Chromosome Abnormalities • Klinefelter Syndrome • Males with 2 X chromosomes (XXY) • Tend to be overweight, tall • Some feminine traits (breasts, higher pitched voice) • Sperm count is low, small testicles • Hormone injections can help

  9. X – Power • There have been no reported instances of babies being born without an X chromosome, indicating that this chromosome contains genes that are vital for the survival and development of the embryo.

  10. Jacob’s Syndrome • XYY Syndrome • Normal male traits • Often tall and thin • Associated with over aggression

  11. Sex Chromosome Mutations • Super Female XXX • Trisomy X • Little or no visible differences • tall stature • learning disabilities • limited fertility

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