Download What is a dominant allele?

AP Biology
Mr. Wallis
Reading Guide: Campbell Chapter 14
Name:
due date:
Chapter 14: Mendel and the Gene Idea
GREGOR MENDEL’S DISCOVERIES
14.1 Mendel used the scientific approach to identify two laws of inheritance
Notes:
 Character:

Trait:

True-breeding:

Hybridization:

Monohybrid Cross:

P generation:

F1 generation:

F2 generation:
Why did Mendel choose to work with peas?
What is the difference between self-pollination and cross-pollination?
The law of Segregation
Notes:
 Alleles:

Dominant allele:

Recessive allele:

Law of segregation:
How did Mendel’s experiments disprove the “blending model of inheritance”?
page 1 of 6
Mendel’s Hypothesis: (explain each of the following in your own words)
1. Alternative versions of genes (different alleles account for variations in inherited characters).
2.
For each character, an organism inherits two alleles, one from each parent.
3.
If the two alleles differ, then one, the dominant allele, is fully expressed in the organism’s appearance; the other,
the recessive allele, has no noticeable effect on the organism’s appearance.
4.
The two alleles for each character segregate during gamete production.
Useful Genetic Vocabulary
Notes:
 Homozygous:

Heterozygous:

Phenotype:

Genotype:
The Testcross
What is a testcross? What is its purpose?
How is it performed?
The law of independent assortment
Notes:

Dihybrid cross

Law of independent assortment
Chapter 14 Reading Guide
page 2 of 6
14.2 The laws of probability govern Mendelian inheritance
The Rule of Multiplication
Explain this rule
The Rule of Addition
Explain this rule
Using Rules of Probability to Solve Genetic Problems
Explain how to use these rules to solve genetic problems
14.3 The relationship between genotype and phenotype is more complex than predicated by Mendelian genetics
Incomplete Dominance
Notes:
 Incomplete dominance
How does incomplete dominance differ from the “blending hypothesis”?
What is a dominant allele?
Notes:
 Complete dominance

Codominance
What are the differences between complete dominance, codominance, and the varying degrees of incomplete
dominance?
Are these variations manifest in homo- or heterozygotes?
Chapter 14 Reading Guide
page 3 of 6
Give some examples of each. Explain.
Summarize the three important points about dominance / recessiveness relationships:
1.
2.
3.
Multiple Alleles
How is blood type an example of multiple alleles?
Pleiotropy
Notes:
 Pleiotropy
Epistasis
Notes:
 Epistasis
Diagram the example of epistasis an explain:
Polygenic Inheritance
Notes:
 Quantitative characteristics

Polygenic inheritance
Chapter 14 Reading Guide
page 4 of 6
Nature Versus Nurture: The Environmental Impact on Phenotype
Notes:
 Multifactorial
Why would nature vs. nurture be a difficult area of genetics to study?
14.4 Many human traits follow Mendelian patterns of inheritance
Pedigree analysis
Notes:
 Pedigree
Copy the pedigrees in figures 14.15 a and b and determine whether the trait is dominant or recessive in each:
Many human disorders follow Mendelian patterns of inheritance
Recessively Inherited Disorders
Notes:
 Carriers

Cystic fibrosis

Tay-Sachs Disease

Sickle-cell disease
Chapter 14 Reading Guide
page 5 of 6
Dominantly Inherited Disorders
Notes:
 Huntigton’s disease
Multifactorial Disorders
What does it mean to say that many diseases have a “multifactorial basis”?
Why would this make it more difficult to study them and/or to treat them?
Additional Questions / Notes
Chapter 14 Reading Guide
page 6 of 6