Exams Fall 1994 Recitation day time TA 7 03 Hour Exam 1 October 5 1994 Write your name on all six pages Indicate your recitation section on this page Write all answers on this handout only Exam begins at 11 05 and ends at 11 55 Time will be announced when 5 and 1 minutes remain Problem 1 Problem 2 Problem3 Total 30 points 30 points 40 ooints 100 points Name 1 The traits in the pedigrees below are comoletely oenetrant 7 1 male a 5 pts 0 female z I affected male 0 affected female The following pedigree shows inheritance of an X linked recessive trait X 9Q What is the probability that a son from the first cousin marriage shown will exhibit the trait b 10 pts The following pedigree shows inheritance of the short eared trait in mice 4 f C SS V i i zr f aut Z i What is the probabilitythat mouse 1 is a heterozygote ii What is the probabilitythat mouse 2 the progenyfrom the brother sister mating will exhibit the short eared phenotype i I Name c 15 ts Huntington s disease is caused by an autosomal dominant allele This pedigree shows inheritance of Huntington s disease in a family Also present in this family is a particular blood antigen which is a recessive trait The Huntington s disease locus and the locus fot the blood antigen are on the same chromosome and are 5 cM apart affected with Huntington s disease exhibits recessive blood antigen n EgP of the individuals shownarebothaffectedwith Huntington s andexhibitthe bloodantigen 4 4 0 14 1 4 or 14 H 4 4 o 4 What is the probability that the indicated grandchild will both exhibit the recessive blood antigen and develop Huntington s disease Please show your work Lo o z s7 Name Wild type humbugs have brown bodies and brown eyes You have isolated mutations in three new humbug genes The mutation sp is dominant and gives humbugs with spotted bodies The mutation gr is recessive and gives humbugs with green bodies The mutation bl is recessive and gives humbugs with black eyes You cross two true breeding mutant strains to produce F1 females heterozygous for sp gr and bl These F1 females are then test crossed to true breeding black eyed green bodied males The phenotypes of 3000 progeny are scored as shown below sp bl gr 53 61 sp bi gr 1390 1347 sp sp gr gr 4 2 70 74 bl bl L 4 p r l 5r r sp r or l r c o l l ur cv r b p r a 5 pts What are the genotypesof the two true breeding parents of the F1 females sip bi r 4 c b 15 pts Draw a map showing the order and distances between the sp gr and bl genes i l p I r I 5 0 o c 10 pts A dominant mutation eyeless ey is identified You want to map ey relative to bl but your lab partner claims this can1 be done sinceyou obviously can t score the presence of black or brown eyes in an eyeless bug You don t agree and you cross a true breeding eyeless bug to a true breeding black eyed bug An F1 female is crossedto a true breeding black eyed male The followingphenotypesare observed in 100 progeny eyeless 51 black eyed 39 p r t I brown eyed 10 rt c b hf Io st Ltl I r r c b f p r l l What is the map distance between bl and ey z o 51 3 I lO x leo ZO Name You have isolated two different yeast strains defective in methionine synthesis met These strains are unable to grow on medium that does not contain methionine When one strain is mated to the other the cliploids can grow on medium that does not contain methionine From this you conclude that the mutations arein different genes which you call met1 and met2 You sporulate the diploids and score 100 tetrads of three types numberoftetrads 75 PD 20 r 5 rj 4 met3 met 1met 2 met 2 met a 10 pt8 Calculate the distance between met1 and met2 dl T r vFO 2 fot l zc 3c xlO0 Z ICC Xto0 Z5 cN b 5 pie YOU are interested in determining the genotypes of the individual spores from one of the tetrads which has four met spores The genotype of each spore clone is tested by mating to each of four test strains that are of either mating type a or mating type a and are either met1 or met2 The results of these mating tests are shown below where indicates that the mating produced diploids that can grow without methionine in the medium Based on the behavior of spores 3 fill in the expected results for spore 4 Remember that in a tetrad there will be two spores of mating type a and two spores of mating type c Also remember that cells of the same mating type can t mate o met1 a met1 o met2 met2 spore 1 4 E spore 2 m 4 m spore 3 4 spore 4 4 c 5 pts A met spore from one of the 2 met 2 met tetrad types is mated to a wild type strain When the diploid is sporulated which of the followingclasses do you expect to occur least frequently and why 4 met ZzLt i fp 1 N D 3 met 1 met 2 met 2 met Name k Recitation day K time TA 7 03 Exam 2 October 28 1994 Write your name on all seven pages Indicate your recitation section on this page Write all answers on this handout only Exam begins at 11 05 and ends at 11 55 Time will be announced Problem 1 Problem 2 Problem3 Total when 5 and 1 minutes 30 points 30 points 40 points 1O0 points remain Name 1 Bacteriophage 13makes plaques on bacterial host strains X14 and G13 Five mutant strains a b and d of 13are able to make plaques on host X14 but not on G13 All five mutations are recessive and fail to complement one another and therefore are in the same gene designated HI In order to map the mutations with respect to one another you coinfect X14 bacteria with pairwise combinations of the mutants and titer the resulting phage on both X14 and G13 hosts The total number of plaques formed on X14 for each cross is 1x10 4 and the number of plaques formed on G13 for each cross is given in the table below a b a 50 c d o b z sO Lo I cM 175 125 C 125 75 z l tS io4 3 5 cAA o 2Xl25 104 2 S M b c 50 d b IS lo c J So io 1 5 M l t a 10 pts Draw a map showing the order of the a b and d mutations and the distances between them in map units I I I t o b c The protein product …
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