+ Pedigrees

+ What is a Pedigree? A) A type of dog food. B) A direct heir from a super rich family. C) A diagram of familial relationships that uses symbols to represent people and lines to represent genetic relationships.

+ Why use a pedigree? A) They make it easier to see the relationships between family members. B) They can help a family to see how and to whom genetic traits have been passed. C) Both A and B are correct. D) It is a good brand of inexpensive healthy dog food.

+ Symbols used in Pedigrees Heterozygous for autosomal recessive Carrier sex-linked recessive Deceased

+ Types of Pedigrees There are 2 types of pedigrees:  Autosomal : Traits that are located on the non-sex chromosomes, Pairs These traits can be inherited through the dominant form or the recessive form. Pedigrees will look different depending on the trait inherited -- recessive or dominant.  Sex-linked : Traits that are located on the sex chromosomes, X or Y. *Carrier symbols are only used in sex-linked pedigrees.

+ 3.For dominant and recessive traits, people who HAVE the trait being analyzed ALWAYS have fully shaded in symbols. * Sex-linked traits use the carrier symbol. 4.Alleles are assigned using the first letter of the trait as follows: (using tongue rolling as an example) For Autosomal Dominant Traits: T = affected t = normal (or CAN roll tongue) (or CANNOT roll tongue) ** A shaded in symbol could be homozygous dominant or heterozygous! The Rules, cont.

+ For Autosomal Recessive Traits: (using Albinoism as an example) A = not affected a = affected (not albino) (albino) * A shaded in symbol will only be homozygous recessive ! 5.Always use a key! List the trait and the symbol to be used. See examples—Tongue Rolling and Albinoism.