Exam2_Study_Guide

 

This study guide highlights materials to help you focus your preparation for exam 2.

As always, the best way to prepare is to study & re-write you class notes while referencing your book, other books, &/or web resources, working the problems in the back of the book, attending the weekly help sessions, and any other tricks (concept maps, vocabulary note cards, study groups) that work for you.

 

END OF CHAPTER 2.

The chi-square test:

Used to compare genetic data to theoretical data that is based on the rules and principles of genetics and inheritance.

You should be able to:

1)    Properly interpret the question

2)    Define the classes (rows in the table)

3)    Calculate the expected values based on your theory

4)    Fill in the and work the table to get a chi-square value (memorize the formula)

5)    Sum of the squared differences obtained for each class/row to obtain the single chi-square value for the entire problem

6)    Use the chi-square along with the degrees of freedom to obtain the P value.

7)    Use the P value to choose "reject the null" or "fail to reject the null."

8)    Note:  You will need a basic functions calculator, and the family of P-value curves will be attached to your exam.

Pedigree analysis:

You should be able to do one or more of the following, depending on the exact question:

1)    Draw a proper pedigree from description of a family history.

2)    Deduce the mode of inheritance from a detailed pedigree.

3)    Assign probabilities for likelihood of a particular genotype or phenotype for individuals.

 

CHAPTER 3: Chromosomal Basis of Inheritance, Sex Linkage, & Sex Determination.

Know:

1)    The chromosome theory of inheritance

2)    The meaning of the terms:
autosome, heterogametic, homogametic, hemizygous, crisscross inheritance, X chromsome nondisjunction, genotypic sex determination, X chromosome-autosome balance system, Barr body, lyonization, TDF (testes-determining factor), SRY, hermaphroditic.

3)    Know the Lyon hypothesis & X-inactivation as a means of equalizing the amount of active genetic X-linked material in males and female.  Know XIC and XIST.

4)    The chromosome balance sex determination system of "the fly" and "the worm".

5)    Define & distinguish between the different types of sex-linked traits.

6)    Know how to recognize X-linked Dominant vs. recessive traits.  For instance, X-linked dominant traits exhibit the pedigree property that an affected father will pass the trait to ALL of his daughters and NONE of his sons (Fig. 3.13b).

7)    Know the chromosomal karyotype for Turner syndrome and for Klinefelter Syndrome.

 

CHAPTER 4: Extensions of Mendelian Genetics.

Know:

1)    The concept of multiple alleles and the relativity of alleles.

2)    Be able to define and give examples of partial/incomplete dominance and
co-dominance.  How many phenotypic classes would you get in a dihybrid F2 if both genes had co-dominant allele pairs?

3)    How allele interactions can alter mendelian ratios.  This is especially true for a di-hybrid cross in which the two genes interact in the same biological or biochemical pathway (such as pigment formation).

4)    How special kinds of alleles (Dominant/Gain of Function alleles or lethal alleles) can affect the number of phenotypic or progeny classes & ratios.

5)    How to describe, define, compare & contrast, or give examples of
partial penetrance and variable expressivity, and what is epistasis.

6)    How to describe, define, etc, sex-limited traits and sex-influenced traits, and how they differ from sex-linked traits described in the previous chapter.

 

CHAPTER 5: Gene Mapping in Eukaryotes

Know:

1)    How do detect recombination and how to generate a linkage map from recombination data of two-point or three-point test crosses.

2)    The meaning and use of coupling (cis) verses repulsion (trans) linkage phases.

3)    The meaning of crossover interference and how to calculate it based on observed and predicted double crossovers.

 

 

CHAPTER 6: Gene Mapping in Bacteria and Phage

Know:

1)    The meaning and usage of bacterial genetics terms such as minimal media, complete media, auxotroph, prototroph, liquid culture, agar/petri plate culture.

2)    How to grow and distinguish auxotrophs from prototrophs
for example: thr- verses thr+, azis vesrses azir.

3)    Conjugation, Lederberg and Tatum's classic experiment, and Davis's U-tube experiment.  Know how conjugation systems (F+ x F-, Hfr x F-, or F-prime x F-) work and how they are used to generate gene maps (& the units of those maps).

4)    Transformation, bacterial

5)    Transduction, by phage, and under what special circumstances it results in transfer of genetic material between bacteria.

6)    The basic structure of T4 phage and lambda phage.  Know the life cycle of a virulent phage & be able to draw and annotate it (as in Fig. 6.11).

7)    The terms prophage, lysogeny and plaque.

8)    The differences and similarities between generalized  & specialized transduction.

9)    The type of experiments used to map phage genes using recombination (Fig 6.17).

 

CHAPTER 7: Non-mendelian genetics.

 

      For this chapter, study the lecture powerpoint slides – they have a lot of information added & written in them.  Important terms & concepts form this chapter include:

      endosymbiont hypothesis, mitochondria, chloroplasts, uniparental inheritance, maternal inheritance, LHON, MERRF, maternal effect, Limnaea shell coiling, dextral, sinistral, genome imprinting (PWS).