1. Mendel’s Laws
Law of Dominance: if the two alleles at a locus differ, then one, the dominant allele, determines the organism′s appearance; the other, the recessive allele, has no noticeable effect on the organism′s appearance Law of Segregation: the two alleles for a heritable character separate (segregate) during gamete formation and end up in different gametes Law of Independent Assortment: each pair of alleles segregates independently of other pairs of alleles during gamete formation

2. Bell Work
In a type of lizard called anoles brown skin is dominant to the color green diagram how genes would be expressed in a heterozygous individual with the genotype Bb
In the example above what does B stand for?

3. Other Inheritance Patterns

4. Incomplete Dominance
The heterozygote has a phenotype that is intermediate between the phenotypes of the two homozygotes.
Example: Petal color in certain flowers.

5. Incomplete dominance example

6. Codominance The heterozygote expresses both traits at the same time.
Example: roan coat color in cattle
Red “Roan” White

7. CWCW x CWCW

8. CRCW x CRCW

9. CRCR x CRCW

10. CRCR x CWCW

11. CRCW x CWCW

12. Color Blind Test

13. Color Blind Test

14. Sex-Linked Inheritance
Genes located on sex chromosomes produce different patterns in males and females.
Females generally have two alleles for these genes.
Males generally have only one allele.
If a male inherits a sex-linked recessive allele from his mother, the allele will be expressed.

15. Red/Green Color Blindness

16. color-blind male x carrier female

17. Continuous variation
Most traits show a range of variation rather than distinct either/or types
This occurs when multiple genes and environmental factors influence the trait’s expression
Continuous variation is often described with frequency distribution tables.

18. Example using actual data

20. Polygenic
Inheritance
Many genes
influence a
single trait

21. Multiple Alleles
For many genes, several alleles exist in the population.
This expands the number of possible genotypes and phenotypes.

22. Example of Multiple Alleles
Human blood type is determined by three alleles: A, B, & O.
IA & IB are codominant.
i is recessive.

24. Linked Genes
Genes located on the same chromosome tend to be inherited together
Such genes are said to be “linked genes.”
When genes are linked, they do not assort independently.

25. Segregation
Alleles segregate when homologous chromosomes separate during Meiosis I.

26. Independent
Assortment