CHAPTER 14Objectives
The student should be able to:
1. Describe several theories of inheritance prior to Mendelian Genetics.
2. Explain how Mendel's hypothesis of inheritance differed from the blending theory of inheritance.
3. List several features of Mendel's methods that contributed to his success.
4. List four components of Mendel's hypothesis that led him to deduce the law of segregation;.
5. State, in their own words, Mendel's law of segregation.
6. Use a Punnett square to predict the results of a monohybrid cross and state the phenotypic and genotypic ratios of the F2 generation.
7. Distinguish between genotype and phenotype: heterozygous and homozygous: dominant and recessive; allele, gene, and gene pair.
8. Define random event, and explain why it is significant that allele segregation during meiosis and fusion of gametes at fertilization are random events.
9. Explain how a testcross can be used to determine if a dominant phenotype is homozygous or heterozygous.
10. Use the rule of multiplication to calculate the probability that a particular F2 individual will be homozygous recessive or dominant.
11. Given a Mendelian cross, use the rule of addition to calculate the probability to determine if a particular individual will be heterozygous.
12. State, in their words, Mendel's law of independent assortment.
13. Give an example of incomplete dominance and explain why it is not evidence for the blending theory of inheritance.
14. Explain how the phenotypic expression of the heterozygote is affected by codominance and incomplete dominance.
15. Describe the inheritance of the ABO blood system and explain codominance with the combination of the alleles for type A and type B.
16. Define and give examples of pleiotropy, epistasis, polygenic inheritance.
17. Describe how environmental conditions can influence phenotypic express.
18. Describe the inheritance and expression of cystic fibrosis, Tay-Sachs disease and sickle-cell anemia
19. Use a human pedigree to demonstrate inherited traits.
20. Explain how a lethal recessive gene can be maintained in a population.
21. Explain why consanguinity increases the probability of homozygosity in offspring.
22. Explain why lethal dominant genes are much more rare than lethal recessive genes.
23. Give an example a late-acting lethal dominant in humans and explain how it can escape elimination.
24. Explain how carrier recognition, fetal testing and newborn screening can be used in genetic screening and counseling.
CHAPTER 14 OBJECTIVES
The student should be able to:
1. Explain how the observations of cytologist and geneticists provided the basis for the chromosome theory of inheritance.
2. Explain why Drosophila meianogaster is a good experimental organism.
3. Define linkage and explain why linkage interferes with independent assortment.
4. Distinguish between parental and recombinant phenotypes.
5. Explain how crossing over can unlink genes.
6. Describe sex determination in humans.
7. Describe the inheritance of a sex-linked gene such as color-blindness.
8. Explain why a recessive sex-linked gene is always expressed in human males.
9. Explain how an organism compensates for the fact that some individuals have a double dosage of sex-linked genes while others have only one.
10. Distinguish among nondisjunction, aneuploidy and polyploidy; explain how these chromosomal changes occur and describe the consequences.
11. Distinguish between trisomy and triploidy.
12. Distinguish among deletions, duplications, translocations and inversions.
13. Describe the type of chromosomal alterations implicated in the following; cri du chat syndrome, Down syndrome, Klinefelter syndrome, extra Y, super-female.
14. Discuss the location and function of cytoplasmic genes.