Transcript pedigree - Mrs. Salmon Science

Springboard
Toolbox #
Genetic Disorders
Normal Chromosomes
Trisomy 21 or Downs Syndrome- affected individuals
live short lives and have severe developmental
problems
Having the wrong number of sex chromosomes often leads
to the inability to reproduce properly.
Sex-linked disorders
Hemophelia- x-linked disorder
where blood can not clot properly,
causing the person to bleed much
more than normal.
Note the recessive x on the mother.
Because males get one x they are
Much more likely to have this trait.
Sex linked gene- an allele
that is inherited with a
sex chromosome.
Recessive Disorders
< Cystic Fibrosis, a condition
where fluid clogs the lungs
intefering with breathing
Sickle Cell>
Blood cells take a sickle shape, clogging the
bloodstream leaving the person weak
A pedigree is a chart used by geneticists
to track the inheritance of a trait over
several generations
Pedigrees allow doctors to determine if a child would
be at risk for developing a condition, or if future
children could pick up that condition.
I
II
III
IV
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2.
3.
4.
Which members of this family have the trait?
Which generation did the trait skip?
Is this trait dominant or recessive?
Would generation 4’s children be at risk inheriting the trait?