Chapter 6: Pedigree Analysis Flashcards
Why are humans bad model organisims?
-controlled mating is not possible
-long generation time
-small family size
Pedigree
a pictorial representation of a family history, a family tee that outlines the inheritance of one or more characteristics
Are pedigrees typically dihybrid or single?
single
Proband
the person from whom the pedigree is initiated
What do pedigrees indicate?
first instance of a trait/disease
What should you look for in pedigrees?
-gender
-generationship
-Who recieves the trait?
What type of traits usually appear equally in males and females and tend to skip generations?
autosomal recessive traits
What is more likely to appear among progeny of related parents?
autosomal recessive traits
What trait usually appears equally in males and females?
autosomal dominant
Why are autosomal dominant triats equal in males and females?
because we both share autosomes
Do autosomal dominant traits skip generations?
yes
How are traits passed in autosomal dominant traits?
unaffected persons do not transmit the trait and affected persons have at least one affected parent
In what does an affected male not pass the trait to his sons but can pass the allele to a daughter?
X-Linked Recessive
Why is daughter passed the trait in X-linked recessive, but they are unaffected?
Due to XX (this is why they are unaffected)
Does an X-Linked Recessive daughter who has a trait, pass the trait to her sons? If so, are they affected?
Yes because they only have one X
Are X-Linked Recessive Traits more frequent in males or females?
males
Do X-Linked dominant traits skip generations?
no
Are X-Linked dominant traits passed to all daughters, and no sons, or all sons and no daughters?
All daughters and no sons
Why do all daughters get X-Linked dominant traits?
Because they have to take Dad’s X
What traits only appear in males?
Y-Linked Traits
Dizygotic Twins
non-identical twins
Are dizygotic twins more genetically identical than normal siblings?
not more genetically identical than siblings
Monozygotic Twins
identical twins
Are monozygotic twins genetically identical?
yes, they came from the same egg/sperm
What is a trait shared by both members of a twin pair?
concordant trait
What is the percentage of twin pairs that are concordant for a trait?
concordance
What allows for assesment of genetic vs. environmental influence on traits?
comparison of concordance values of MZ twins vs. MZ twins
