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Genetics-4.3.12,10.3.1,10.3.2. David Barkley Taylor 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. .
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Genetics-4.3.12,10.3.1,10.3.2 David Barkley Taylor 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 Inheritance • Wheat • Kernel color in wheat is determined by two gene pairs • crossing 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)
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
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>.