Other Patterns of Inheritance Chapter 11.3 Other Patterns of Inheritance This presentation demonstrates the new capabilities of PowerPoint and it is best viewed in Slide Show. These slides are designed to give you great ideas for the presentations you’ll create in PowerPoint 2011! For more sample templates, click the File menu, and then click New From Template. Under Templates, click Presentations.

1 2 3 4 Four exceptions to Mendel’s principles Incomplete Dominance 2 Co-dominance 3 Multiple Alleles 4 Polygenic Traits In most organisms, heredity is more complicated than Mendel realized

Incomplete Dominance- 1 Incomplete Dominance- Some alleles are neither dominant NOR recessive!!

Incomplete dominance Continued For Example: Four O’Clock Flowers Heterozygous type lies somewhere between the 2 homozygous types- IT’s A BLEND

Incomplete Dominance Con’t Heterozygous type lies somewhere between the 2 homozygous types- A BLEND!! Incomplete Dominance Con’t Red + White = Pink

2 Co-dominance Phenotypes produced by both alleles are clearly expressed

BOTH TRAITS EQUALLY STRONG NOT BLENDED! TRAITS STAY DISTINCT AND UNIQUE BOTH TRAITS EQUALLY STRONG

In some chickens, the gene for feather color is controlled by co-dominance. The allele for black is B and the allele for white is W. The heterozygous, BW, phenotype is known as erminette, or speckled.

You can do a lot more with movies in PowerPoint 2011. Movies can be embedded in your presentation. That’s right, no more lost movies! Also, you can recolor the entire movie or apply a movie style easily. Your movies will look great! Erminette chickens- examples of CODOMINANCE- both traits show up distinctly

Other examples of Co-dominance Ie: In humans, gene for protein that controls cholesterol levels in the blood Ie: Roan cows- A white cow and red bull makes red and white spotted offspring, also known as "roan”.

"What is the difference between co-dominance and incomplete dominance Co-dominance happens when there are two dominant alleles for a trait and they are both shown. For example, a red and white flower would make a striped flower. A white cow and brown cow makes a brown and white spotted cow, also known as "roan”. Incomplete dominance happens when there are two dominant alleles for a trait and they are blended (mixed). For example, a red flower and a white flower would make a pink flower.

3 Multiple Alleles Many genes exist in several different forms, so they are said to have multiple alleles.

Multiple Alleles Continued For example: coat color in rabbits, there is ONE gene with at least FOUR different alleles

Multiple Alleles Continued Another Example: Human blood type

Traits controlled by 2 or more genes Polygenic Traits Traits controlled by 2 or more genes

Many traits are produced by interaction of several genes For example: at least 3 genes control reddish-brown pigment in eyes of fruit flies

Many traits are produced by interaction of several genes For example: more than 4 genes control skin color in humans

Many traits are produced by interaction of several genes More examples of Polygenic traits: Hair and eye color in humans http://www.allaboutvision.com/conditions/eye-color-chart.htm

Genes and the Environment Environmental conditions (internal or external) can affect gene expression

Temperature affecting butterfly color Pontia occidentalist, from western North America is light in color when emerges in the summer, and darker in color when it emerges in the spring p.321

Internal environment & genes Genes and the environment: another example… gene for male pattern baldness is found in both males and females, but the male hormones TRIGGER it. Internal environment & genes

1 2 3 4 Review: Four exceptions to Mendel’s principles Incomplete Dominance 2 Co-dominance 3 Multiple Alleles 4 Polygenic Traits In most organisms, heredity is more complicated than Mendel realized

Other patterns of inheritance What’s Your Message?