11.2 Complex Patterns of Inheritance

1. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Incomplete Dominance • The heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes.

2. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Codominance • Both alleles are expressed in the heterozygous condition.

3. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Multiple Alleles • Blood groups in humans • ABO blood groups have three forms of alleles.

4. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Coat Color of Rabbits • Multiple alleles can demonstrate a hierarchy of dominance. • In rabbits, four alleles code for coat color: C, cch, ch,and c.

5. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Coat Color of Rabbits Chinchilla Albino Light gray Dark gray Himalayan

6. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Sex Determination • Sex chromosomesdetermine an individual’s gender.

7. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Dosage Compensation • The X chromosome carries a variety of genes that are necessary for the development of both females and males. • The Y chromosome mainly has genes that relate to the development of male characteristics. • Chromosome inactivation • Barr bodies

8. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Polygenic Traits • Polygenic traits arise from the interaction of multiple pairs of genes.

9. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Environmental Influences • Environmental factors • Diet and exercise • Sunlight and water • Temperature

10. Complex Inheritance and Human Heredity Chapter 11 11.2 Complex Patterns of Inheritance Twin Studies • Helps scientists separate genetic contributions from environmental contributions • Traits that appear frequently in identical twins are at least partially controlled by heredity. • Traits expressed differently in identical twins are strongly influenced by environment.

11. Complex Inheritance and Human Heredity Chapter 11 11.3 Chromosomes and Human Heredity Telomeres • Telomere caps consist of DNA associated with proteins. • Serves a protective function for the structure of the chromosome

12. Complex Inheritance and Human Heredity Chapter 11 11.1 Basic Patterns of Human Inheritance Inferring Genotypes • Knowing physical traits can determine what genes an individual is most likely to have. Predicting Disorders • Record keeping helps scientists use pedigree analysis to study inheritance patterns, determine phenotypes, and ascertain genotypes.

13. Complex Inheritance and Human Heredity Chapter 11 11.3 Chromosomes and Human Heredity Karyotype Studies • Karyotype—micrograph in which the pairs of homologous chromosomes are arranged in decreasing size. • Images of chromosomes stained during metaphase • Chromosomes are arranged in decreasing size to produce a micrograph.

14. 1 2 1 2 3 Pedigree = Males Key: = Females Shading = Have trait (Attached Earlobes = f ) No Shading = Do not have trait (Free Earlobes = F) I II

15. I F F ff F 1 2 3 4 F ff II 1 2 3 4 5 6 F F ff F 1 2 3 F F F What are the Genotypes of the people shown below? f f f ? ? ? f f f f

16. - - - - - - - - - What Does Each One Show? Divorce Adoption Not Married but Biological mom and dad Divorce and Death