Lecture 28 Flashcards
What is a quantitative trait?
Phenotypes that vary continuously (height, mass); exhibit complex relationship between genotype/phenotype, likely polygenic, may have environmental influences, ranges may overlap
Define continuous characteristics/traits
Characteristics vary along a scale of measurement with many overlapping phenotypes; usually quantitative
Define discontinuous characteristics/traits
Traits that possess only a few phenotypes (red or white petals); usually qualitative
What are threshold characteristics?
Measured by presence or absence; susceptibility to disease
Define standard deviation
Square root of the variance
What is an appropriate sample?
Subset of the population that should be representative of the larger population and unbiased (not tailored to support your hypothesis)
What is a GWAS (Genome Wide Association Study)?
Examination of many common genetic variants in different individuals to see if any variant is associated (co-segregates) with a trait
Define polygenic inheritance
Occurs when one characteristic is controlled by two or more genes
Define variance
Variability within a group of measurements
The measurements of a distribution with a higher _____ will be more spread out.
a. Mean
b. Variance
c. Standard deviation
d. Both b and c
D. Both B and C since they are related
Define the correlation coefficient
Statistical measure of the strength of the association; perfect correlation is 1, negative coefficient indicates an inverse relationship
Define regression and regression coefficient
Regression: predicting the value of one variable, if the value of the other is given
Regression Coefficient: represents the slope of the regression line, indicating how much one value changes on average per increase in the value of another variable
In Lubbock, TX, rainfall and temperature exhibit a significant correlation of -0.7. Which conclusion is correct?
a. There is usually more rainfall when the temperature is high
b. There is usually more rainfall when the temperature is low
c. Rainfall is equally likely when the temperature is high or low
B. There is usually more rainfall when the temperature is low
How do calculate broad-sense heritability and narrow-sense heritability?
Broad: ratio of total genetic variance to total phenotypic variance
Narrow: ratio of additive genetic variance to the total phenotypic variance