Pedigrees

For your notes: Copy the following Draw I II 1 2 3 4 5 identifying

Pedigrees Diagrams that display the occurrence of a genetic trait in a family through generations

How do I read a pedigree? 1. Circles represent females 2. Squares represent males Horizontal lines represent marriages 1 2

How do I read a pedigree? Vertical lines represent children A shaded circle or square means that individual has the trait 1=Mom, 2=Dad 3&5 =daughters 4 = affected son 1 2 5 3 4

How do I read a pedigree? Roman numerals indicate generations I = grandparents II = parents III = children

Dominant Pedigree At least one parent of an affected individual must exhibit the trait

Recessive pedigree An individual that shows the trait may not have parents that show the trait All children of affected parents will show the trait

Sex linked Pedigrees Sex linked traits (x-linked) are more common in males There are no direct male to male transmission because males transmit their Y chromosome to sons