Download Chapter 9: Patterns of Inheritance

Chapter 9: Patterns of Inheritance
Chapter Objectives
I)
Mendel’s Laws
A) Describe pangenesis theory and the blending hypothesis. Explain why both ideas are now rejected.
B) Explain why Mendel’s decision to work with peas was a good choice.
C) Define and distinguish between true-breeding organisms, hybrids, the P generation, the F1 generation, and
the F2 generation.
D) Define and distinguish between the following pairs of terms: genotype and phenotype; dominant allele and
recessive allele; heterozygous and homozygous.
E) Define a monohybrid cross
F) Describe the genetic relationship between homologous chromosomes.
G) Explain how Mendel’s law of independent assortment applies to a dihybrid cross. Illustrate this law with
examples from Labrador retrievers and Mendel’s work with peas.
H) Explain how family pedigrees can help determine the inheritance of many human traits.
I) Explain how recessive and dominant disorders are inherited. Provide examples of each.
II)
Variations on Mendel’s Laws
A) Describe the inheritance patterns of incomplete dominance, multiple alleles,
codominance, pleiotropy, and polygenic inheritance. Provide an example of each.
B) Explain how the sickle-cell allele can be adaptive.
C) Explain why human skin coloration is not sufficiently explained by polygenic inheritance
III)
The Chromosomal Basis of Inheritance
A) Define the chromosome theory of inheritance.
B) Explain the chromosomal basis of the laws of segregation and independent assortment.
C) Explain how linked genes are inherited differently from nonlinked genes.
IV)
Sex Chromosomes and Sex-Linked Genes
A) Compare the sex determination system in humans to those in fruit flies, grasshoppers, birds, and bees.
B) Describe patterns of sex-linked inheritance, noting examples in fruit flies and humans.
C) Explain why sex-linked disorders are expressed much more frequently in men than in women.
Key Terms
ABO blood groups
Allele
carrier
codominant
complete dominance
cross-fertilization
dihybrid cross
dominant allele
F1 generation
F2 generation
genotype
hemophilia
heterozygous
homozygous
hybrid
incomplete dominance
linked genes
monohybrid cross
P generation
phenotype
pleiotropy
polygenic inheritance
recessive allele
sex chromosome
sex-linked gene
trait
true-breeding