Patterns of Inheritance

1. Patterns of Inheritance Ch. 10

2. Mendel’s Laws • Mendel’s First Law: The Law of Segregation • The two copies of a gene separate during meiosis and end up in different gametes. • This begins to show the probability of offspring. • Can be shown via Punnett square

3. Mendel’s Laws • Mendel’s Second Law: The Law of Independent Assortment • When gametes form, the separation of the 2 copies of one gene during meiosis is independent and separate from each other gene

4. Beyond Mendel • Mendel’s results with his pea plants showed complete dominance • This pattern is not always the case. • We also have incomplete dominance, co-dominance, multiple allele traits, polygenic traits, and epistatic genes, for starters.

5. Incomplete Dominance • Formation of a new phenotype in heterozygotes that appears as an intermediate of the two original phenotypes. • Red + white = pink flowers

6. Co-Dominance • The formation of a new phenotype that appears in the heterozygote that is a combination of the two original phenotypes • Red + white = red with white spots in flowers

7. Multiple Allele • There are more than 2 alleles present within a population. It is the combination of the alleles present that give you your phenotype. • Hair color in rabbits. Several types.

8. Polygenic Traits • Traits that are distinguished by multiple genes on the genome • Skin color in humans

9. Reading Questions • This was finalized in 1979. There have been many advancements in DNA technology since then. How could these advancements change the results? Is there cause to look at them again? What else could be done to prove or disprove the connection? • There are instances when mutations occur that could change the genotype of the offspring quite a bit from the parents. Provide 1 piece of evidence from the reading to show this is NOT the case.