Genetics-4.3.12,10.3.1,10.3.2David BarkleyTaylor Turner

Polygenic Inheritance Polygenic inheritance is the inheritance

of a characteristic that is controlled by more than one gene.

Human traits that show continuous variation include weight, height and skin color.

Polygenic Inheritance This means that something simple, like

skin color, is affected by more than one gene from ones parents. Each allele of a polygenic character will offer a little bit of information to the whole phenotype.

Polygenic Inheritance Human skin color is a good example to

visually see how more than one gene can affect appearance.

Polygenic Inheritance

In humans there are at least three genes coding for skin color. Each skin color gene has two forms; one form codes for high levels of melanin production, and the other form codes for low levels of melanin production

Polygenic InheritanceWheatKernel color in wheat is

determined by two gene pairscrossing individuals with the

phenotype extremes yield offspring that are a 'blend' of the two parents

Polygenic Inheritance When these homozygotes are crossed

the offspring are all double heterozygotes AaBb

two double heterozygotes are crossed-http://staff.jccc.net/pdecell/evolution/polygen.html

4.3.12 Deduce the genotypes

and phenotypes of individuals in

pedigree charts.

Pedigrees: Are used to illustrate the mode of

inheritance (dominant or recessive) Give clues to the mode of inheritance of

the disease Show potential threat to other family

members

Phenotypes: Observable and measurable charaterics

in an organisms Effects of genetic coding and

environment Ex:

eye color

Genotypes: Genetic composition of organisms With respect to the specific traits they describe Refers specifically to genetic code (environment

has no effect)

Type of Inheritance

Autosomal Dominant Inheritance Requires only one parent to

carry the dominant gene in order for children to be affected.

Autosomal Recessive Inheritance

Requires for both parents must carry the recessive gene for offspring to be affected.

X-Linked Dominant & Recessive Inheritance

More common in boys because they only need one gene

A mother gives the dominant or recessive gene male offspring and the father gives the Y chromosome.

Pedigree Vs. Punnett Square A punnett square is used to determine

the out come of two alleles being crossed

Contrarily a pedigree is used to find modes of inheritance for genetic diseases

Extra Pedigree Practice www.zerobio.com/drag_gr11/pedigree/pedigree_overview.htm

I’M MY OWN GRANDPA

Works Cited " 10.3.2 Explain that polygenic inheritance can contribute to continuous variation using two

examples, one of which must be human skin color. ." ARHicks — Just another Edublogs.org weblog. N.p., n.d. Web. 9 Feb. 2012. <http://arhicks.edublogs.org/2011/06/07/10-3-2-explain-that-polygenic-inheritance-can-contribute-to-continuous-variation-using-two-examples-one-of-which-must-be-human-skin-color/>.

"Define polygenic inheritance - IB Biology Syllabus." IB Biology Syllabus Home - IB Biology Syllabus. N.p., n.d. Web. 9 Feb. 2012. <http://ibbiology.wetpaint.com/page/Define+polygenic+inheritance>.

"Explain that polygenic inheritance can contribute to continuous variation - IB Biology Syllabus." IB Biology Syllabus Home - IB Biology Syllabus. N.p., n.d. Web. 9 Feb. 2012. <http://ibbiology.wetpaint.com/page/Explain+that+polygenic+inheritance+can+contribute+to+continuous+variation>.

"Gene Interactions." Estrella Mountain Community College. N.p., n.d. Web. 9 Feb. 2012. <http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookgeninteract.html>.

"Genetic engineering and biotechnology." IB Guides. N.p., n.d. Web. 12 Feb. 2009. <www.ibguides.com/biology/notes/genetic-engineering-and-biotechnology>.

"IB Biology Syllabus." Biology for Life. N.p., n.d. Web. 9 Feb. 2012. <http://www.biologyforlife.com/course%20info/Syllabus/Syllabus.htm#Topic_10:__HL_Genetics>.

"Polygenic inheritance." JCCC Staff and Faculty Pages. N.p., n.d. Web. 13 Feb. 2012. <http://staff.jccc.net/pdecell/evolution/polygen.html>.