Chp 9 Why This
Chapter Matters
1. Humans have long relied on
selective breeding to produce specialized breeds of livestock and pets.
Mendel’s principles of inheritance are fundamental to the workings of
artificial selection.
2. Variations of Mendel’s laws
explain the inheritance patterns of many human traits and diseases.
3. Determining
the probability of genetic diseases by following patterns of inheritance
enables us to anticipate disease
and better address its consequences. Pedigrees and genetic testing are an increasingly
common part of modern medicine.
4. Genetics and
the inheritance of traits are fundamental to understanding evolution by natural selection.
Chapter Objectives
Biology and Society: Our
Longest-Running Genetic Experiment: Dogs
1. Explain how
human experiences breeding dog and food crops can provide insights into
principles of genetics.
Heritable Variation and
Patterns of Inheritance
2. Define and
distinguish between self-fertilization, cross-fertilization, purebred
organisms, hybrids, the P generation, the F1 generation,
and the F2 generation.
3. Define and
distinguish between the following pairs of terms: heterozygous
versus homozygous, dominant allele
versus recessive allele, genotype
versus phenotype, and
phenotypic ratio versus genotypic
ratio.
4. Define the
law of segregation and explain how it applies to reproduction.
5. Define Mendel’s law of independent
assortment and explain how it applies to a dihybrid
cross.
6. Explain how a
testcross can be performed to determine an organism’s genotype.
7. Explain how
and when the rule of multiplication should be used to determine the
probability of an event.
8. Explain how a
pedigree is used to determine how a particular human trait is inherited. Define
a carrier and explain how carriers are revealed in human pedigrees.
9. Compare the
frequency and method of inheritance of recessive and dominant disorders.
Explain how a dominant lethal allele can be inherited.
Variations on Mendel’s Laws
10. Define and distinguish between complete dominance,
incomplete dominance, and codominance.
11. Describe the selective advantage of people
who are heterozygous for sickle-cell disease.
12. Define and distinguish between pleiotropy and polygenic inheritance. Describe examples of
each.
13. Explain how the environment influences the
expression of traits.
The Chromosomal Basis of
Inheritance
14. Define the chromosome theory of
inheritance and explain how linked genes are inherited differently from nonlinked genes.
15. Explain why researchers used fruit flies
and how they created linkage maps.
Sex Chromosomes and
Sex-Linked Genes
16. Explain how chromosomes determine the sex
of a human.
17. Explain why sex-linked diseases are more
common in male humans.
18. Describe the general characters of the
following sex-linked disorders in humans: red-green colorblindness and
hemophilia.
Evolution Connection: Barking
Up the Evolutionary Tree
19. Describe the relationships between the
many breeds of dogs.