QUIZ 2

1. Spoon is a little too lucky with the bones at the Hustler’s Ball.  Three goons grab him and his dice and take them into the backroom, but they can’t find anything suspicious when they look at the dice.  Unfortunately for Spoon, Big Johnny has a Masters in statistics from Brown and knows just what to do.  He rolls one of the dice 1200 times and calculates a chi-squared value of 10.21 based on the number of times that each number showed up on that die.  Does Spoon get to walk out of their alive? Why or why not?
  
He should be allowed to live. Df=5, which means that p>0.05 for chi2=10.21.  Therefore they can not reject the null hypothesis that the dice are fair.  However, these guys might not be so nice, and may make just kill him for being below p=0.10 (obviously the students don’t have to get that last line).

2.

The genes A,B,C are located on the same chromosome in Neurospora crassa.  The following ordered asci were obtained from the cross:     abC    X   ABc

45	5	146	1	10	20	15	58	
abC	abC	abC	abC	abC	abC	abC	abC	
Abc	aBC	abC	ABC	aBc	ABc	abc	AbC	
aBC	Abc	ABc	abc	AbC	abC	ABC	aBc	
ABc	ABc	ABc	ABc	ABc	ABc	ABc	ABc	

Determine the gene order and distances between gene-gene and gene-centromere.  Present your results by drawing out the chromosome and labeling the genes, the centromere and the appropriate distances separating them.

Answer:  For a and b
distance between a and b = (1/2 (45+5+10+58)+3(0)/300  *100= 19.7

distance between a and centromere = (1/2(45+1+20+58))/300  *100 = 20.7 
distance between b and centromere = (1/2(5+1+10+20))/300 *100 = 6

b and c

distance between b and c = 1/2(66))/300   *100 = 11
between c and centromere = (1/2)(45+10+20+15)/300  *100 = 15

a and c
distance between a and c = 1/2(84)/300  * 100 = 14

*----6---b---------11------------c------------------14----------------------a------------

3.
In the following pedigree, the generation I father is known to be afflicted with an X-linked dominant trait.  Fill in the pedigree to reasonably portray the inheritance of this disease within the rest of the family.

Answer.  All generation II females will be affected with the disease.  Approximately half of the offspring from the female in generation II will be affected.