Study Guide 4:  How are Traits Inherited? (Chapter 4, 5, 6)

1.      Be able to recognize, define, and use the following terms from Chapter 4:

Dominant                               Recessive                                     Law of Segregation

Homozygous dominant          Homozygous recessive                Heterozygous

Genotype                               Phenotype                                    Alleles

Gametes                                 Meiosis                                        Genotypic ratio

Phenotypic ratio                     Punnett Square                            Pedigree Analysis

2.      What is the meaning of dominance and recessiveness?

3.      For an autosomal dominant trait, use Punnett Squares to determine the genotypic ratios and phenotypic ratios of the following crosses:

a.  FF x ff                                   b.  Ff x Ff                                      c.  Ff x ff

4.      For an autosomal recessive trait, use Punnett Squares to determine the genotypic ratios and phenotypic ratios of the following crosses:

a.  FF x ff                                   b.  Ff x Ff                                      c.  Ff x ff

5.      Be able to give and recognize examples of autosomal dominant traits and autosomal recessive traits (see Table 4.2).

6.      From a human pedigree, determine whether the trait is autosomal dominant or autosomal recessive, and determine the genotypes of the individuals diagrammed in the pedigree.

7.      Be able to recognize, define, and use the following terms from Chapter 5:

Lethal alleles                               Incomplete Dominance            Codominance

Multiple Alleles                          Epistasis                                  Pleiotropy

Maternal Inheritance                   Mitochondria                           Gene Linkage

8.      For autosomal dominant lethals and for autosomal recessive lethals, use Punnett Squares to determine the genotypic ratios and phenotypic ratios of the following crosses:

a.  FF x ff                                   b.  Ff x Ff                                c.  Ff x ff

9.      For a trait where there is incomplete dominance, use Punnett Squares to determine the genotypic ratios and phenotypic ratios of the following crosses:

a.  FF x ff                                   b.  Ff x Ff                                c.  Ff x ff

10.    For human ABO blood typing, use Punnett Squares analysis to determine genotypic ratios and phenotypic ratios and use Pedigree Analysis to determine individual genotypes.

11.    What is gene linkage?  How does crossing-over affect the degree of gene linkage?

12.    For an X-linked dominant trait, use Punnett Squares to determine the genotypic ratios and phenotypic ratios  for a cross between any given parental types.

13.    For an X-linked recessive trait, use Punnett Squares to determine the genotypic ratios and phenotypic ratios  for a cross between any given parental types.

14.    From a human pedigree, determine whether the trait is autosomal or X-linked and dominant or recessive.  Then determine the genotypes of the individuals diagrammed in the pedigree.

15.       What is X inactivation?  Why does X inactivation occur?  What is the Barr Body?