7/4/2019 Today’s Agenda… Bellringer: Identify the following as homozygous or heterozygous: A. TT B. Ww C. yy D. Ss Notes on Genetics Since Mendel #12 Worksheet for Homework Free template from www.brainybetty.com

February 16th Study Pack #12 Page 314 Genetics Since Mendel February 16th Study Pack #12 Page 314

7/4/2019 Today’s Goals… I can explain how traits are inherited by incomplete dominance. I can compare multiple alleles and polygenic inheritance, and give examples of each. I can explain how the gender of offspring is determined. Free template from www.brainybetty.com

Unexpected Results After Mendel scientists did more work with genetics 7/4/2019 Unexpected Results After Mendel scientists did more work with genetics Four o’clock plants Crossed purebred red-flowered plants with purebred white flowered plants Expected to get all red flowers Instead all the flowers were pink! Free template from www.brainybetty.com

Unexpected Results Neither allele for flower color was dominant 7/4/2019 Unexpected Results Neither allele for flower color was dominant An intermediate (middle) phenotype was produced - pink flowers Free template from www.brainybetty.com

7/4/2019 Incomplete Dominance When two parents combine to create a middle phenotype it is called incomplete dominance Free template from www.brainybetty.com

7/4/2019 Incomplete Dominance Page 314-315 Palomino Horses

Multiple Alleles Mendel studied traits that had just two alleles 7/4/2019 Multiple Alleles Mendel studied traits that had just two alleles A trait can have multiple alleles Multiple alleles produce more phenotypes of a trait If you have three different alleles, imagine all the combinations possible Free template from www.brainybetty.com

Multiple Alleles Example: Blood Type The alleles are A, B, O 7/4/2019 Multiple Alleles Example: Blood Type The alleles are A, B, O O is recessive to A and B When a person inherits both A and B, they have bloodtype AB 4 phenotypes possible: A, B, AB, 0 Free template from www.brainybetty.com

Polygenic Inheritance 7/4/2019 Polygenic Inheritance Polygenic Inheritance occurs when a group of gene pairs acts together to produce a trait This produces a wide variety of phenotypes Examples: Height, shades of eye and skin color 3-6 gene pairs control your skin color and more may control your hair and eye color Free template from www.brainybetty.com

Polygenic Inheritance 7/4/2019 Polygenic Inheritance Your environment can also play a role in your traits Environmental factors can be internal or external Chemicals in the body of some birds cause them to be more brightly colored A person who is at risk for skin cancer can avoid the sun Free template from www.brainybetty.com

Polygenic Inheritance 7/4/2019 Polygenic Inheritance What environmental factors might affect the size of leaves on a tree? Amount of water or sunlight available Chemicals in the soil Temperature and weather conditions Free template from www.brainybetty.com

7/4/2019 Compare What is the difference between multiple alleles and polygenic inheritance? Polygenic Inheritance involves many GENES as opposed to many forms of the same gene Free template from www.brainybetty.com

Gender Determination One pair of chromosomes determines gender 7/4/2019 Gender Determination One pair of chromosomes determines gender In females, they are labeled as XX In males, they are labeled as XY The chromosomes received from the mother and the father determine the gender of the offspring Free template from www.brainybetty.com

Homework Worksheet – Genetics Challenge 7/4/2019 Free template from www.brainybetty.com