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Pedigrees. I can analyze a pedigree in order to determine genotypes and phenotypes of individuals and predict mode of inheritance (i.e. autosomal dominant or recessive, or sex-linked) in a family. Pedigree. A chart showing the genetic connections between individuals A genetic family tree
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Pedigrees I can analyze a pedigree in order to determine genotypes and phenotypes of individuals and predict mode of inheritance (i.e. autosomal dominant or recessive, or sex-linked) in a family.
Pedigree • A chart showing the genetic connections between individuals • A genetic family tree • Often groups of people whose heritage is well documented or who are somewhat isolated from others are used to develop pedigrees. • E.g. Icelanders, Mormons, Ashkenazi Jews, Amish, Sardinians
Pedigree Symbols male female marriage/mating offspring in order of birth, from left to right Individual showing trait being studied sex not specified generation I, II, III, IV...
Human Genetic Abnormalities/Disorders • Different patterns of inheritance are observed depending on the condition: • Autosomal Recessive Inheritance • Autosomal Dominant Inheritance • X-linked inheritance
Autosomal vs. sex-linked traits • Autosomal traits are caused by genes on autosomes (chrms #1- #22) • autosomal recessive or autosomal dominant traits or diseases • Sex-linked traits are caused by genes on the sex chrms (X or Y) • X-linked recessive or X-linked dominant traits or diseases
Autosomal Recessive Inheritance If parents are both heterozygous, child will have a 25% chance of being affected
Autosomal Recessive Inheritance • Unaffected parents can have affected kids • Disease not found in every generation • Boys and girls equally affected
Autosomal Dominant Inheritance • Affected parents can have affected kids • Disease often found in every generation • Boys and girls equally affected
Pedigree showing X-linked recessive inheritance I • Males show disorder more than females • Son cannot inherit disorder from his father II III IV