Semester 1, Day 9

1. Semester 1, Day 9 Modes of Inheritance

2. Agenda • Review for Mendelian Genetics Quiz • Turn in Homework (Section 10.1) • Take Mendelian Genetics Quiz • Lecture on Modes of Inheritance • Silent Work/Reading Time • Group Work/Reading Time

3. Review for Mendelian Genetics • How to determine the probability a child will be male or female • What is the definition of a dominant allele? A recessive allele? • Define genotype, phenotype, heredity, and zygosity • What is the zygosity of the following genotypes: AA, Aa, aa? • Given a genotype (AA, Aa, aa), determine the phenotype. • Know the TITLES and DEFINITIONS of both of Mendel’s Laws • Be able to do a monohybrid Punnett square • Determine which letters to use to represent genotypes • Fill in the Punnett square correctly • Determine probabilities • Be able to do a dihybrid Punnett square • Determine the four possible groups of alleles a person can pass on (FOIL) • Fill in the Punnett square correctly • Determine probabilities

4. Turn in Homework • Section 10.1 • Cornell Notes • Section Assessment: #1-6 • Chapter 10 Assessment • 2, 3, 7, 8, 11, 12, 14, 16, 17, 20-24

5. Mendelian Genetics Quiz • Corrections: • #5 – Change (Fill in “orange” or “pink”) to (Fill in “red” or “purple”) • #8.d – Change ‘homozygous recessive black fur’ to ‘homozygous recessive WHITE fur’ • #8.f – Change ‘if a cat with homozygous recessive black fur mates’ to ‘if a cat with homozygous recessive WHITE fur mates’. • Reminders: • Take quiz silently • When finished, flip quiz over • Eyes on your own paper

6. Albinism

7. Modes of Inheritance • Basic Patterns of Inheritance • Mendelian Genetics • Homozygous Dominant: 2 Dominant Alleles, Shows Dominant Trait • Heterozygous: 1 Dominant Allele, 1 Recessive Allele, Shows Dom. Trait • Homozygous Recessive: 2 Recessive Alleles, Shows Recessive Trait • Recessive Genetic Disorders • Recessive allele codes for disorder • Dominant allele codes for healthy A = normal melanin production a = abnormal melanin production

8. Modes of Inheritance • Basic Patterns of Inheritance: Mendelian Genetics (cont.) Heterozygous, carry dominant (healthy) allele & recessive (disorder) allele; only shows dominant trait Example: Mom and Dad are carriers Genotype Probabilities AA = 1 / 4 = 25% (homozygous dominant) Aa = 2 / 4 = 50% (heterozygous) aa = 1 / 4 = 25% (homozygous recessive) Phenotype Probabilities Pigmented (Non-Carrier) = 25% Pigmented (Carrier) = 50% Albino = 25% A a Female Carrier! AA Aa A Aa aa a Male Child

9. Huntington’s Disease • http://www.youtube.com/watch?v=65xf1olEpQM

10. Modes of Inheritance • Basic Patterns of Inheritance: Mendelian Genetics (cont.) • Dominant Genetic Disorders • Dominant allele codes for disorder • Recessive allele codes for healthy Genotype Probabilities AA = 0 / 4 = 0% (homozygous dominant) Aa = 2 / 4 = 50% (heterozygous) aa = 2 / 4 = 50% (homozygous recessive) Phenotype Probabilities Huntington’s = 50% Healthy = 50% H h Female Carrier! Hh hh h H = Huntington’s h = Healthy Hh hh h Male Child

11. Modes of Inheritance • Complex Patterns of Inheritance • Incomplete Dominance • Neither allele is fully dominant over the other • Heterozygous condition BLENDS phenotypes Example R = red flower W = white flower Use uppercase for both alleles Genotype Probabilities RW = 4/4 = 100% Heterozygous RR = 0/4 = 0% Homozygous Dominant WW = 0/4 = 0% Homozygous Dominant Phenotype Probabilities Pink = 100% R R Female Mom is a red snapdragon (RR) Dad is a white snapdragon (WW) RW W W Male Child

12. Modes of Inheritance • Complex Patterns of Inheritance (cont.) • Codominance • Neither allele is fully dominant over the other • Heterozygous condition shows BOTH phenotypes Example B = Black Cat T = Tan Cat Use uppercase for both alleles Genotype Probabilities TB = 4/4 = 100% Heterozygous BB = 0/4 = 0% Homozygous Dominant TT = 0/4 = 0% Homozygous Dominant Phenotype Probabilities Tabby (Black & Tan Stripes) = 100% Mom is a black cat (BB) Dad is a tan cat (TT) B B Female T T TB Male Child

13. Modes of Inheritance • Complex Patterns of Inheritance (cont.) • Multiple Alleles • There are more than 2 allele forms for a trait • **Note: However, you still only get one allele copy from each parent for a total of 2 copies per child Example (also shows codominance) IA = blood type A (dominant) IB = blood type B (dominant) i = blood type O (recessive) IA i Female Codominant IAIB IBi IB Mom is IAi (heterozygous Type A) Dad is Ibi (heterozygous Type B) IAi ii i Male Child

14. Modes of Inheritance • Complex Modes of Inheritance: Multiple Alleles (cont.) IA i Female IAIB IBi IB IAi ii i Male Child

15. Modes of Inheritance • Complex Modes of Inheritance: Multiple Alleles (cont.) Example #2 Mom = IAIB Dad = IAi IA IB Female IAIA IAIB IA IAi IBi i Male Child

16. Modes of Inheritance • Complex Patterns of Inheritance (cont.) • Sex-Linked Traits • Traits controlled by genes located on a sex chromosome (X-linked traits more common) • Recall: Female (XX), Male (XY) • X-linked traits expressed in males more b/c they only have one X chromosome • X-linked traits expressed in females less b/c the other X chromosome usually masks (hides) the trait

17. Red-Green Color Blindness

18. Modes of Inheritance • Complex Modes of Inheritance: Sex-Linked Traits (cont.) Example XB = normal sight Xb = red-green color blind Y = Y chromosome Mom = XBXb Dad = XBY Genotype Probabilities XBXB = 1 / 4 = 25% XBXb = 1 / 4 = 25% XBY = 1 / 4 = 25% XbY = 1 / 4 = 25% Phenotype Probabilities Female & Healthy = 1 / 2 = 50% Female & Carrier = 1 / 2 = 50% Female & Color-Blind = 0 / 2 = 50% Male & Healthy = 1 / 2 = 50% Male & Carrier = 0 / 2 = 0% Male & Color-Blind = 1 / 2 = 50% XB Xb Female XBXB XBXb XB XBY XbY Y Male Why can’t a male be a carrier?? Child

19. Reading/Work Time • Read Chapter 12 • Questions: • 12.1 #1-5 • 12.2 #1-5 • 12.3 #1-5 • Chapter 12 Assessment # 1-18, 20-25 • First 30 Minutes: Silent Work Time • Remaining Time: Group Work Time (conditional)