Download Codominance Multiple Alleles Incomplete Dominance Polygenic

Polygenic Inheritance
Incomplete Dominance
Codominance
Complex Characters
Multiple Alleles
Polygenic Inheritance
Traits that are influenced by several genes
Ex: height, eye color, skin color
Click here for a
Polygenic
Inheritance Problem
using Skin Color as
http://www.ccfc.ca/English/images/diversity.gif
an example
Skin color may involve at least four pairs of alleles with nine
(or more) shades of skin color
Complex Characters
Influenced by both genes AND the
environment
Ex: Height
-Determined by an unknown number of
genes AND factors such as nutrition and
disease
http://www.saintaugustinespriory.org.uk/prospectus/images/tall_and_short.jpg
Incomplete Dominance
When two alleles are present (heterozygous
genotype), there is a new BLENDED phenotype.
A red carnation parent mated to a
white carnation parent produces pink Individuals who are heterozygous for
s.c.a. show a mild form of the disease
offspring
Sex Influenced and Sex Limited Traits
NOT carried on the X or Y chromosomes
Both men and women carry the genes, but the presence of
hormones changes how the genes are expressed.
Ex: Male pattern
baldness is dominant in
men and recessive in
women because of the
influence of
testosterone in men.
Ex: Beard growth
Annie Jones
Madame Delait
Baroness
Sidonia de
Barcsy
Genetic Screening
Amniocentesis:
http://amniocentesis.upmc.com/Images/Sub/ImageAmnio.jpg
Chorionic Villi Sampling:
http://www.shands.org/health/surgeries/images/19163.jpg
Both procedures involve removing fetal cells to analyze the chromosomes.