Pedigree Charts

Pedigree The recorded ancestor of an individual

Pedigrees and Animals Can be used to track animal breeding and enhance desirable traits through selective breeding (i.e. Dog breeds, horses, etc.)

Studying human genetics You cannot make humans of different types breed together Pedigree charts offer an ethical way of studying human genetics

Studying human genetics Today genetic engineering has new tools to offer doctors studying genetic diseases A genetic counsellor will still use pedigree charts to help determine the distribution of a disease in an affected family

Studying human genetics Pedigrees can be used to study the transmission of a genetic condition in a family Can help predict the likelihood that a child will inherit a genetic disorder

Studying human genetics Can diagnose whether a genetic condition as dominant or recessive Can help parents make decision about having children (family planning)

Symbols used in pedigree charts A marriage with five children, two daughters and three sons. The eldest son is affected by the condition. Eldest child  Youngest child Normal male Affected male Normal female Affected female Marriage © 2007 Paul Billiet ODWS

Organizing the pedigree chart A pedigree chart of a family showing 20 individuals © 2007 Paul Billiet ODWS

Organizing the pedigree chart Generations are identified by Roman numerals I II III IV © 2007 Paul Billiet ODWS

Organizing the pedigree chart Individuals in each generation are identified by Arabic numerals numbered from the left Therefore the affected individuals are II3, IV2 and IV3 I II III IV © 2007 Paul Billiet ODWS

What type of disorder is this?

Autosomal Recessive Disorders In an autosomal recessive disorder individuals can inherit the condition even if neither of their parents are affected The condition can “skip” a generation

What type of disorder is this? Autosomal Recessive

What type of disorder is this?

Autosomal Dominant Disorder Individuals only inherit the disorder when a parent is affected The disorder will not “skip a generation” In most families, the children have a 50% probability of having the disorder.

What type of disorder is this? Autosomal Dominant