Figure: 11-10 Title: Incomplete dominance. Caption: The inheritance of flower color in snapdragons is an example of incomplete dominance. (In such cases, we use capital letters for both alleles, here R and R '.) Heterozygtes ( RR ') have pink flowers, whereas the homozygotes are red ( RR ) or white ( R ' R ').
Figure: 11-15a Title: Sickle-cell anemia. Caption: (a) Normal red blood cells are disc-shaped with indented centers. (b) The red blood cells of a person with sickle-cell anemia become sickled.
Chapter 9 genetics handout fall 2011
CHAPTER 9 PATTERNS OF INHERITANCE (GENETICS) I. The Foundation of Genetics II. Basic Terminology III. Modern Principles of Inheritance IV. Solving Genetics Problems A. Monohybrid Cross V. Sex-Determination and Sex-Linked Traits VI. Non-Mendelian Patterns of Inheritance VII. Human Genetic Disorders/Conditions VIII. How Phenotypes are Affected by Non-genetic Factors (Environment)
I. The Foundation of Genetics <ul><li>______________(mid-1800s) </li></ul><ul><li>- Austrian monk, Father of Genetics </li></ul><ul><li>- studied inherited ________ in edible garden peas by </li></ul><ul><li>making hybrids </li></ul>
<ul><li>1884 – Mendel died </li></ul><ul><li>1900s – his work was _________________ by </li></ul><ul><li>Carl Correns </li></ul><ul><li>Hugo de Vries </li></ul><ul><li>Erich Tshermak </li></ul><ul><li>II. Basic Terminology </li></ul>
<ul><li>III. Modern Principles of Inheritance (Based on Mendel’s Work) </li></ul><ul><li>1. Each trait is determined by a ____________; an organism has two _____________ for each gene. </li></ul><ul><li>2. Law of Dominance genotype Aa Bb </li></ul><ul><li>3. Law of Segregation Aa Bb </li></ul><ul><li>4. Law of Independent Assortment AaBb </li></ul>A a B b Ab aB ab AB gametes gametes
V. Sex-Determination and Sex-linked Traits X chromosome Y chromosome Fig. 9-14 p. 144
VI. Non-Mendelian Patterns of Inheritance A. Multiple Alleles and Co-dominance e.g., human blood types
Genotype AA, Ao BB, Bo AB oo (Universal donor) Frequency in the U.S. (Universal recipient ) Table 9-1 p. 146 Human Blood Group Characteristics
B. Polygenic Inheritance - when several genes influence a ____________________ e.g., eye color skin color father mother
VII. Human Genetic Disorders or Conditions - mutations - A. Due to abnormal # of autosomes e.g., Down syndrome or ____________ Fig. 9-22a p. 153
Baby with Down syndrome Typical Down syndrome’s hands and feet
Genetic test for Down syndrome ( F luorescence I n S itu H ybridization or FISH) Fig. 9-23 p. 153
Why are there 3 copies of chromosome # 21? ________________________: - the failure of chromatids to separate during anaphase II
B. Due to chromosomal deletions or presence of several repeats of a DNA sequence 1) Cri-du-chat syndrome - “ ___________________________” (French) - deletion of short arm of chromosome # 5 - severely impaired _____________________
2) Fragile X syndrome - multiple copies of GAT can inactivate the entire _________________________ - the most common form of inherited _________________________________ - attention deficit, ____________________ - large ears, long face, flat feet
C. Due to imbalance in the # of the X and Y chromosomes 1) Turner syndrome - X 1/3000 live births (females) 2) Trisomy X - XXX 1/1500 3) Klinefelter syndrome – XXY 1/1000 males 4) Jacob Syndrome – XYY 1/1000 males
D. Due to single gene mutations or defects 1) Due to X-linked recessive alleles a) hemophilia b) red-green colorblindness c) Duchenne muscular dystrophy d) cleft palate 2) Due to autosomal gene defects (recessive) a) sickle cell anemia - abnormal ____________________
Normal red blood cells Sickle cells (abnormal red blood cells)
b) Cystic fibrosis - non-functional _______________________ - produce excessive _______________ - lung infections
D. Due to single gene defects…continued 3) Due to dominant alleles e.g., Huntington’s disease - delayed onset disease - brain slowly deteriorates: ___________ - loss of ________________________ - painful paralysis - Huntington gene – Chro. # 4 (1993) - huntingtin protein forms aggregates in __________________ which die off
VIII. How Phenotypes are Affected by Non-genetic Factors (Environment) A) Himalayan rabbit genotype = BB or Bb B = black fur phenotype? = __________________________________ Why???
- enzyme producing black pigment - ______________ at 93 ° F (34 ° C) B) Colors of pea flowers - ________________________________________ C) Height - _________________________________ D) Skin color - ________________________________ E) Intelligence F) Susceptibility to cancer