Bio 180 Lecture 16:01

Ex leaf shape in the water buttercup ranunculus

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Unformatted text preview: cats. Ex. Leaf shape in the water buttercup (Ranunculus aquatilis). Ex. Color in hydrangea flowers. Epistasis / Gene x Gene Interactions - Interactions can occur between genes at different loci. - Epistasis = when phenotype produced by an allele depends on actions of genes at other loci. Ex. Fruit color in Bell Peppers Gene 1 (red pigment) R = Red r = Yellow Genotype R -Y rrYR-yy rryy Gene 2 (chlorophyll prod.) Y = Absence of green y = Presence of green Phynotype Red Yellow Brown Green wheat tha suits of a and white eny form Ehle prop (b) Crosses between pure lines produce novel colors. Parental generation x The pa contro and aa Brown Yellow • The th 1 F ind 1/4 X 1 F generation Red 2 F generation Red 9/16 Yellow 3/16 Brown 3/16 (c) Model to explain 9 : 3 : 3: 1 pattern observed above: Two genes interact to produce pepper color. Green 1/16 • The a, tion, b ductio of red case a makes Later virtually independ amount Ex. Coat color of Labrador retrievers Gene 1 (melanin production): B, b Gene 2 (melanin deposition in hair): E, e Genotype B -E bbE--ee Phenotype Black Brown Yellow Polygenic Inheritance = - Each locus contributes small amount to phenotype. - Produces “Quantitative Trait” - range of phenotypes. - Continuous, bell-shaped (normal) distribution of phenotypes in population. - Opposite to “Discrete Traits”. Ex. Kernel color in wheat 3 independent genes control degree of red pigmentation aabbcc white AaBbCc AABBCC medium red deep red Ex. Human height, weight, and skin color...
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This note was uploaded on 02/24/2014 for the course BIOL 180 taught by Professor Freeman during the Winter '07 term at University of Washington.

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