Download GENETICS Read chapters 14 and 15 in Campbell. Key Terms: F1 F

GENETICS
Read chapters 14 and 15 in Campbell.
Key Terms: F1
P
recessive characteristic
allele
heterozygous
phenotype
test cross
dihybrid cross
multiple alleles
sickle cell anemia
sex chromosome
X chromosome
sex-linked characteristic
linked genes
polytene chromosomes
duplication
inversion
trisomy
F2
dominant characteristic
locus (loci)
homozygous
genotype
monohybrid cross
partial dominance (incomplete dom.)
epistasis
mutation
pleiotropic gene
autosome
Y chromosome
Barr body
crossing-over
translocation
deletion
nondisjunction
polyploid
Answer the following questions:
1. Explain Mendel's laws (Dominance, Independent Assortment , & Segregation).
Relate each of these laws to chromosomal behavior during meiosis.
2. Differentiate between the two terms in each of the following pairs: dominant recessive, allele - gene, F1 - F2, homozygous - heterozygous, phenotype genotype, monohybrid - dihybrid.
3. Explain how incomplete dominance differs from complete dominance.
4. Use a Punnett square or the multiplication of probabilities to find the characteristic
phenotypic ratios in the F2 generation of a cross involving two characters (dihybrid)
in which the two genes are independent (not linked). Explain how gene
interactions, such as those involving epistatic and modifier genes, could alter this
ratio.
5. Explain why statistical analysis is a useful genetic tool.
6. List the possible genotypes of persons of each blood type (A, B, AB, and O) and
explain the mode of inheritance. Then explain the importance of these blood types
in giving blood transfusions; for example, explain why someone with type AB blood
could not donate blood to a person with type O, while someone with type O blood
could donate blood to someone with type AB.
7. Explain why most mutations are deleterious and how it is possible for a harmful
recessive allele, even a lethal one, to persist in a population.
8. Differentiate between the terms sex chromosome and autosome, and explain the
term sex-linked characteristic.
9. Explain how sex is determined genetically in human beings. Then discuss the
pattern of inheritance of sex-linked characters, showing why recessive sex-linked
characters are expressed more often in males than in females.
10. Use a Punnett square or the multiplication of probabilities to do problems involving
sex linkage. (See Genetics Problems Sheet)
11. Explain the concept of linkage. Show how crossover frequencies are calculated and
how they can be used to make chromosomal maps; then explain why the relative
distances between genes on Drosophila chromosomal maps formulated from
crossover data do not exactly match the corresponding distances on maps derived
from salivary-chromosome studies, while the order of the genes on the
chromosomes is the same in both.
12. Explain the process of nondisjunction and show how it affects the chromosomal
composition of a cell.
13. Explain how translocations, deletions, duplications, and inversions alter
chromosomal composition. Which of the above would you predict would have the
most severe effect? The least severe effect? Explain.
òComplete Genetics Problems at the end of Ch14 (#'s 1-19) work with a partner
òComplete Genetics Problems at the end of Ch15 (#'s 1-16)