Defining polygenic inheritance A characteristic which is controlled by one or more gene. “Multi-factorial” inheritance – Mendel Multi-gene inheritance

Polygenic conditions Skin color Obesity Cancer Diabetes

Things that can affect polygenic conditions Environment – Ex. A person who tans may have darker skin.

Polygenic Inheritance Explains how genes can continuously vary Examples of this are a person’s height, blood type, and skin color

Polygenic inheritance differentiates skin color

Polygenic inheritance affects blood type

4.3.12

Genotype and phenotype Genotype: The entire set of alleles in an organism. Usually written with letters Phenotype: Alleles that include all characteristics based on the genotype. Ex: tallshort – TTtt – Tt – Tt/ Tall

Co-dominance Co dominant Alleles: A pair of alleles that are both affect the phenotype when present in a heterozygote. Example: red flower + white flower= pink flower To write co dominance the main letter should relate to the gene and the suffix to the allele *draw on board Heterozygote: having two different alleles for the same gene

Pedigree Chart Pedigree Chart: Pedigree charts are used to record blood lines in families. They can be used to figure the probability of an offspring and the donor of certain diseases. : affected male : affected female : male : female

Inheritance Autosomal Dominant – You only need to get the abnormal gene from one parent in order for you to inherit the disease. Autosomal Recessive – Two copies of an abnormal gene must be present in order for the disease or trait to develop.

Inheritance Sex-linked Dominance – A single abnormal gene on the X chromosome can cause a sex-linked dominant disease. Sex-linked Recessive – An abnormal gene on both X chromosomes causes a sex-linked recessive disease

Disease and Pedigree Color Blindness: A condition that is caused by genetic factors. Is determined by a carrier of the recessive trait Females have two chromosomes, so to have color blindness she would need two recessive alleles. The male has only one X chromosome and just needs one recessive allele to be affected.

Pedigree Bingo! 1. Obtain a blank pedigree chart, and an orange, yellow, red, and blue colored pencil. 2. Color in the circles for the Grandmother. Make them a variety of your colors. 3. Then do the same for the Grandfather using different colors. 4. Next, close your eyes and randomly pick a colored pencil. Choose 3 examples from Grandmother and 3 examples from Grandfather. 5. Color in these circles for their first child, a daughter. Then complete these steps again for the rest of their children. 6.Next, look at the son and his partner. Make the partner have all 6 circles red. 7. Randomly pick colors from the Son and his partner. Because his partner has all red, 3 circles will be red, and 3 circles will randomly be chosen from the father. 8. Do this for all 3 children. 9. Analyze the results.

Results! – Red = high risk of heart disease – Orange = medium risk of heart disease – yellow= low risk of heart disease – Negative risk of heart disease

Works cited Me/Science-Ideas-and-Concepts/Genotype-and-phenotype