Quantitative Traits (Part 1)

Quantitative traits are what the trait looks like in a ___________ (a smooth range

population (describes phenotype pattern)

Polygenic is how many ______ control the trait

genes (describes genetic cause)

Multifactorial traits are traits shaped by a combination of multiple genes and _____________ influences working together

environmental

Quantitative Patterns are inheritance patterns where a trait shows a smooth, __________ range of phenotypes

continuous (contributing small additive effects)

Multiple-gene hypothesis is the explanation for _____ that smooth range happens in quantitative traits

why (because each gene adds a small amount)

Discontinuous traits are traits with only a few clear ________ and no in between traits

categories (ex- blood type: A,B,AB,O)

Continuous Traits are traits that ____ every possible value in a smooth range

show

Phenotypic variation is a the natural __________ in physical traits among individuals

differences

Normal Distribution is a ____ shaped curve where most values cluster around the ________ and fewer appear at the extremes

bell; average

Histogram is a graph that shows how ______ different ranges of values appear in dataset

often

Measurements of Average

1. Mode

2. Median

3. Mean

Mode is the value that appears the most _____ in a dataset

often (2,3,4,4,5,4,7)

Median is the _______ value in a dataset (smallest—largest)

middle (3, 5, 8)

Mean is the _______ of a dataset

average (add values—divide by values)

Variance measures how ______ out the values in a dataset are

spread (look at how far each value is from the mean)

Standard Deviation shows how much the values in a dataset ______ from the mean

differ

Small Standard Deviation the data points are _____ together

close

Large Standard Deviation the data points are _______ out

spread

Covariance measures how two variables _______ together

change (whether they move in the same direction or in opposite directions)

Positive Covariance is when both variables tend to _______ together

increase

Negative Covariance is when one increases while one __________

decrease

Correlation coefficient __ measures the strength and direction of the linear relationship between two variables

r

Quantitative Traits are either ____________ or ______________

polygenic; multifactorial

Additive allele ________ equally to the phenotype

contributes

Nonadditive allele _________ contribute to the phenotype

doesn’t

Polygenic Inheritance is when a trait in controlled by several genes, each _______ a small amount to the phenotype

adding (adding small doses of a gene to the trait)

Phenotypic Variance is the total amount of variation in a trait within a population which includes:

1. Genetic Differences

2. Environment Differences

3. Interactions (between genes and environment)

Hereditability tells ___ much of the variation you see in a trait due to genes, not environment

how