week 2: multifactorial inheritance Flashcards
- Identify and describe the characteristics of diseases and other traits that demonstrate multifactorial inheritance.
- complex traits aggregate in families
- do not follow mendelian mode of inheritance
- need to distinguish between clustering in families due to genetic factors and those shared due to environmental factors
- no simple relationship between genetic variant and trait when looking at the population
- Give specific examples of diseases and other traits that demonstrate multifactorial inheritance.
cystic fibrosis (has alleleic heterozygosity)
Type 2 diabetes
late onset AD
- Describe the strategies used to determine the relative importance of genetic vs. non-genetic factors in contributing to the variation in a complex trait.
twin studies: compare monozygotic (share 100% of genetic sequence) to dizygotic (share 50% of genetic sequence) twins
-if twins raised together and assume same degree of similar environment than differences in concordance rate between monozygotic and dizygotic twins is due to genetic factors
other option: compare monozygotic twins raised in different environments- same traits assumed are due to genetic factors
adoption studies: have two biologically related siblings, as well as an adopted sibling raised in the same environment as one of the biologically related sibligns
traits between biological siblings that end up being shared are due to genetic facotrs
trait between bilogical/adoptive du eto environmental
- Recognize the potential difficulties associated with quantifying the role of genetic factors in contributing to risk of disease at both the population level and the individual level.
one issue: many simple mendelian traits have one or more characteristics common with a complex trait
- variable disease progression depending on other factors
- different alleles in same gene associated with varying levels of severity
- jsut hard to nail down influence of environment
