What is the difference between genes in coupling configuration and genes in repulsion? How does the arrangement of linked genes (whether they are in coupling or repulsion) affect the results of a genetic cross?

A serotype is a:

A. type of blood cells

B. personality type

C. antibody grouping

D. a grouping bigger than a species

E. a variety of sero

What types of compounds in bacterial cells can serve as antigens?

Why is interference important? Why do we calculate it in a three-point cross? Why don't we calculate interference in a two-point cross?

Why is the frequency of recombinant gametes always half the frequency of crossing over?

The rate of crossing over between two linked genes $(r$ and $w)$ is $0.44$. The following cross is carried out: $R r W w \times r r w w$. What proportion of the gametes of the $R r W w$ parent were recombinant gametes? Explain your reasoning and state any assumptions you made.

The locations of six deletions have been mapped to a Drosophila chromosome, as shown in the following deletion map. Recessive mutations a, b, c, d, e, and f are known to be located in the same region as the deletions, but the order of the mutations on the chromosome is not known.

Chromosome

Deletion 1 $\rule{1cm}{0.4pt}$
Deletion 2 $\rule{1cm}{0.4pt}$
Deletion 3 $\rule{1cm}{0.4pt}$
Deletion 4 $\rule{1cm}{0.4pt}$
Deletion 5 $\rule{1cm}{0.4pt}$
Deletion 6 $\rule{1cm}{0.4pt}$

When flies homozygous for the recessive mutations are crossed with flies heterozygous for the deletions, the following results are obtained, in which “m” represents a mutant phenotype and a plus sign (+) represents the wild type. On the basis of these data, determine the relative order of the seven mutant genes on the chromosome

$$\begin{equation} \begin{array}{ccccccc} &{\text { Mutations }} \\ \text { Deletion } & \boldsymbol{a} & \boldsymbol{b} & \boldsymbol{c} & \boldsymbol{d} & \boldsymbol{e} & f \\ 1 & \mathrm{~m} & + & \mathrm{m} & + & + & \mathrm{m} \\ 2 & \mathrm{~m} & + & + & + & + & + \\ 3 & + & \mathrm{m} & \mathrm{m} & \mathrm{m} & \mathrm{m} & + \\ 4 & + & + & \mathrm{m} & \mathrm{m} & \mathrm{m} & + \\ 5 & + & + & + & \mathrm{m} & \mathrm{m} & + \\ 6 & + & \mathrm{m} & + & \mathrm{m} & + & + \end{array} \end{equation}$$

A group of geneticists are interested in identifying genes that may play a role in susceptibility to asthma. They study the inheritance of genetic markers in a series of families that have two or more asthmatic children. They find an association between the presence or absence of asthma and a genetic marker on the short arm of chromosome 20 and calculate a lod score of 2 for this association. What does this lod score indicate about genes that may influence asthma?

Shown below are eight DNA sequences from different individuals.

$$\begin{array}{cccc} {\text { Nucleotide Position }} \\ \hline \mathbf{1} & 5 & 10 & 15 \end{array}$$

Sequence $1 \ldots$ T C T G G A T C A T C A C A T ...
Sequence 2... A C A G C A T C A T T A C G T...
Sequence $3 \ldots$ T C A G G A T C A T T A C A T ...
Sequence $4 \ldots$ T C A G G A T C A T T A C A T ...
Sequence $5 \ldots$ A $C$ A $\mathrm{G} C$ A T C A T T A C G T...
Sequence 6... T C T G G A T C A T C A C A T ...
Sequence 7... T C A G G A T C A T T A C A T ...
Sequence $8 \ldots$ A C A G C A T C A T T A C G T...

a. Give the nucleotide positions of all single-nucleotide polymorphisms (SNPs; nucleotide positions where individuals vary in which base is present) in these sequences.
b. How many different haplotypes (sets of linked variants) are found in these eight sequences?
c. Give the haplotype of each sequence by listing the specific bases at each variable position in that particular haplotype.

Which of the following factors contribute to psychopathology?

a. family factors

b. social factors

c. psychological factors

d. genetic factors

e. all of the above can contribute to psychopathology

The scientific discipline that uses ecological theory to study, design, manage, and evaluate productive agricultural systems to conserve critical resources is known as
a. integrated pest management
b. sustainability
c. agroecology
d. none of the above

Fine spines (s), smooth fruit (tu), and uniform fruit color (u) are three recessive traits in cucumbers, the genes for which are linked on the same chromosome. A cucumber plant heterozygous for all three traits is used in a testcross, and the following progeny are produced by this testcross:

$$\begin{array}{lllr} S & U & T u & 2 \\ s & u & T u & 70 \\ S & u & T u & 21 \\ s & u & t u & 4 \\ S & U & t u & 82 \\ s & U & t u & 21 \\ s & U & T u & 13 \\ S & u & t u & \frac{17}{230} \end{array}$$

a. Determine the order of these genes on the chromosome.
b. Calculate the map distances between the genes.
c. Determine the coefficient of coincidence and the interference among these genes.
d. List the genes found on each chromosome in the parents used in the testcross.

Priscilla Lane and Margaret Green studied the linkage relations of three genes affecting coat color in mice: mahogany (mg), agouti (a), and ragged (Rg). They carried out a series of three-point crosses, mating mice that were heterozygous at all three loci with mice that were homozygous for the recessive alleles at these loci (P. W. Lane and M. C. Green. 1960. Journal of Heredity 51:228–230). The following table lists the progeny of the test crosses :

$$\begin{array}{cccr} a &\hspace{1cm} R g & \hspace{1cm}+ &\hspace{1cm} 1 \\ + & + & m g & 1 \\ a & + & + & 15 \\ + & R g & m g & 9 \\ + & + & + & 16 \\ a & R g & m g & 36 \\ a & + & m g & 76 \\ + & R g & + & 69 \\ \text { Total } & & & \frac{69}{213} \end{array}$$

a. Determine the order of the loci that encode mahogany, agouti, and ragged on the chromosome, the map distances between them, and the coefficient of coincidence and the interference among these genes.
b. Draw a picture of the two chromosomes in the triply heterozygous mice used in the test crosses, indicating which of the alleles are present on each chromosome.

Waxy endosperm $(w x)$, shrunken endosperm (sh), and yellow seedlings $(v)$ are encoded by three recessive genes in corn that are linked on chromosome 5. A corn plant homozygous for all three recessive alleles is crossed with a plant homozygous for all the dominant alleles. The resulting $\mathrm{F}_1$ are then crossed with a plant homozygous for the recessive alleles in a three-point testcross. The progeny of the testcross is

$$\begin{array}{cccr} w x & s h & V & 87 \\ W x & \text { Sh } & v & 94 \\ W x & \text { Sh } & V & 3,479 \\ w x & s h & v & 3,478 \\ W x & s h & V & 1,515 \\ w x & S h & v & 1,531 \\ w x & S h & V & 292 \\ W x & s h & v & \underline{280} \\ \text { Total } & & & 10,75 \end{array}$$

a. Determine the order of these genes on the chromosome.

b. Calculate the map distances between the genes.

c. Determine the coefficient of coincidence and the interference among these genes.