Pedigrees

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Pedigrees Karyotypes
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Pedigrees

• Used to explore human genetics
• Circles Female
• Squares Male
• Traits
• Not Shaded Do not have
• ½ Shaded Carrier
• Full Shade Have

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Modes of Inheritance

• Autosomal or Sex-Linked
• Autosomal chromosomes other than sex
  chromos.
• Sex linked X or Y
• Dominant or Recessive

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Autosomal Recessive

• equal in males females
• Often skips generations
• May show carriers (half shaded) but not always!

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Autosomal Dominant

• Does not skip generations
• Affect crossed with unaffected 50 of offspring
  are typically affected

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Sex-Linked Traits

• Mostly males
• Mother of affected male is a carrier or affected.
• No male carriers, but can have female carriers

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Pedigree Flowchart

• How many males females are
• affected?

Affected Males Affected Females Autosomal
More Males Sex Linked Trait
No male carriers?
No Does the trait skip a generation?
Are carriers present?
Yes Recessive
No Dominant
Yes Recessive
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Human Karyotypes

• Diploid organisms
• 46 Chromosomes
• 23 homologous pairs
• 2 sex chromos.
• Used to detected
• aneuploidy associated
• disorders

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Nondisjunction

• Not coming apart
• Abnormal chromosome s in gametes
• Causes Aneuploidy

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Down Syndrome

• Trisomy
• Three bodies
• Chromosome 21
• autosomal
• 1/800 US births
• Mild severe

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Sex Chromosomes Disorder

• Turners Syndrome
• Female with only one X
• XO
• Causes Sterility no sex organ development at
  puberty
• Short stature
• Webbed neck

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• Klinefelters Syndrome
• Males with an extra X
• Reduced fertility
• Less testosterone
• 1/1000 males
• XYY
• Normal reproduction
• Delay motor skills
• temper

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X Chromosome

• No cases of babies born without an X chromosome
• X is vital for normal development

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Y Chromosome

• Important role in sex determination
• Y presence creates a male no matter how many
  extra Xs
• Exception Swyer syndrome

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