Ch. 28 - Quantitative Genetics

exam 2

focus on traits that can be described numerically such as height, weight, skin color, and metabolic rate

quantitative genetics

traits that are influences by multiple gene and env. factors

quantitative traits

quantitative genetic is important because

all of the above

quantitative traits are the only traits that ______measurably among individuals in a population

vary

a type of quantitative trait: height, weight, pigmentation on flowers, corn, etc

anatomical traits

a type of quantitative trait: metabolic rate, running speed, milk production, tolerance of env. factors

physiological traits

a type of quantitative trait: meting calls, courtship rituals, learning

behavioral traits

a type of quantitative trait: predisposition to disease

disease trait

quantitative traits can be influenced by

many genes and enviroment

quantitative traits that are expressed as whole numbers (ex: number of bristles on drosophilia)

meristic traits

quantitative traits that are expressed as present or absent depending on predisposition or threshold (ex: a person become diabetic after a genetic combination passes threshold)

threshold traits

many quantitative traits show ______ variation within a population

continuum

quantitative data ranges in value forms a ________, showing how many indv fall into each measurement range

frequency distribution

most indv lie on ______

average or intermediate values

fewer indv lie on _____

extremeties

most quantitative traits are _______, exhibiting continuum of phenotypic variation

polygenic

refers to the transmission of traits that are governed by two or more genes, opposite of ploitopetry

polygenic inheritance

refers to the location of a chromosome that affects the outcome of a quantitative trait

quantitative trait loci (QLT)

how are QLT regions identified

gene mapping

this geneticist performed a continuous variation experiment on tobacco plants

Kolreuter

this geneticist studied the inheritance of red pigment in the hull of wheat

Nilsson-Ehle

proposed the multiple-gene or multiple-factor hypothesis

Bateson

the multiple-gene and/or multiple-factor hypothesis states

implies that many genes or factors contribute to the phenotype in an additive way

the effect of additive alleles at each locus is ____

equivalent

low env effect results in ________ on bell shaped graph/distribution

well defined categories, seperate

high env effects result in _______ on bell shaped graph/distribution

more phenotypic variation in categories