Pedigree Is a Chart That Show the Genetic Relationship Between Individuals in a Family

SBI 3UE Genetic

PEDIGREE NOTATION

·  Pedigree is a chart that show the genetic relationship between individuals in a family

PEDIGREE ANALYSIS

Autosomal Dominant Features
·  Presence of affected individuals in successive generations
·  Equal number of affected males and females
·  Each affected individual usually has at least one affected parent
·  Two affected parents have unaffected offspring
·  Unaffected individuals who marry unaffected individuals rarely have affected offspring / Autosomal Recessive Features:
·  Unaffected parents have affected offspring
·  Equal number of affected males and females
·  All offspring are affected when both parents are affected
·  In rare disorders, affected children who are the offspring of marriages between first cousins or other closely-related family members

X-Linked Dominant Features

·  Each generation usually has an affected individual
·  All daughters of affected males are affected
·  Both sons and daughters of an affected heterozygous female may be affected
·  Generally, twice as many females as males /

X-Linked Recessive

·  All sons of an affected mother are affected
·  Affected fathers never transmit the trait to their son
·  Unaffected parents may have affected offspring
·  Generally, there are more males than females