Chapter 9 Review
Experimental genetics began in an abbey garden
1. Who was Gregor Mendel, and why is he considered to be the “father of genetics?”
2. List three reasons why Mendel was so successful in his research.
3. Define the following terms:
a. true-breeding varieties
b. hybrid
c. P generation:
d. F1 generation
e. F2 generation
Mendel’s law of segregation: define
1. Define monohybrid cross.
2. Describe the four hypotheses developed by Mendel.
3. Define the following terms.
a. allele:
b. homozygous:
c. heterozygous:
d. dominant allele:
e. recessive allele:
4. Explain Mendel’s principle of segregation.
5. Define phenotype and genotype
6. Explain why individuals with different genotypes can have the same phenotype.
Homologous chromosomes bear the two alleles for each characteristic
1. Explain the connection between Mendel’s principles and homologous chromosomes.
The law of independent assortment is revealed by tracking two characteristics at once
1. Define dihybrid cross.
2. Explain Mendel’s principle of independent assortment.
Mendel’s laws reflect the rules of probability – Punnett Squares
After reading this module, you should be able to use the rule of multiplication to made predictions
about the outcome of genetic crosses. You will be expected to do some of these problems on the
exam.
Genetic traits in humans can be tracked through family pedigrees
. Important points:
1
• “Dominant” does not imply that a phenotype is normal or more common.
• Wild type traits are not necessarily dominant.
• Recessive traits may be more common than dominant traits.
1. Define pedigree.
2. Explain what it means if someone is a carrier of a genetic disorder.
Many inherited disorders in humans are controlled by a single gene
1. Name and describe the most common lethal genetic disease in the United States.
2. Aside from customs and laws, why is it GENETICALLY a bad idea to mate with close relatives
and produce offspring
Many genes have more than two alleles in the population
1. Define codominant.
In the ABO blood groups, A and B are codominant, while O is recessive.
A single gene may affect many phenotypic characteristics
1. Define pleiotropy.
2. Explain why sickle-cell disease is an example of pleiotropy.
3. If sickle-cell disease is so devastating, why is the sickle-cell allele so common?
A single characteristic may be influenced by many genes
1. Define polygenic inheritance.
2