genetics problem set 2012

8/12/2019 Genetics Problem Set 2012

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AP Biology Name ________ KEY_________________Problem Set #5: Genetics and DNA Period 1 ! " 5 $

Reminder: Problem Sets are individual assignments. You are welcome to discuss these questions with your classmates,however your answers should be your own. Use your own words. Any academic code violations will result in a zero on thisassignment and a note in your academic record.

1. A grandmother is trying to determine who the father of her granddaughter is. Her daughter has type A blood. Thegranddaughter has type B blood.

What are the possible blood types of the father of this child? _______AB or A____________

Show your wor!%&e mot&er co'ld be BB ()B)B* or B+ ()Bi* b't since t&e grandda'g&ter is A, t&en t&e mot&er m'st be B+ (since s&em'st gi-e &er da'g&ter an + allele, not a B*. %&e grandda'g&ter co'ld be A+ ()Ai* or AA ()A)A*, b't since t&e mom&as B ty/e blood, &er da'g&ter m'st be A+. %&is means t&e grandda'g&ter &as to get an A allele 0rom &er 0at&erSo t&e 0at&er co'ld be A+, AA, or ABt&is means t&e 0at&er2s blood ty/es co'ld be A or AB.

". Hemophilia is a recessi#e se$%lined trait. Specifically& the allele that codes for this disease is found on the 'chromosome ('h). *ndi#iduals with this disorder are unable to form blood clots properly and often run the ris of bleedingto death from in+uries that might normally be considered minor. A couple would lie to now if the child they aree$pecting could be born with hemophilia. The mother,s genotype is 'H'h. The father,s genotype is 'H- and he does nothemophilia.a) $plain what a se$%lined trait is. How is this different from a se$%limited trait? A se3 lin4ed trait is a trait &ose

alleles are 0o'nd on a se3 c&romosome. A se36llimited trait is one t&at may not be on t&e se3 c&romosomes b'tis ty/ically e3/ressed based on t&e se3 o0 t&e indi-id'al.

b) What are the possible genotypes for the couple,s children? 787&, 787&, 7&Y, 78Y

c) What is the / chance that their child will ha#e hemophilia if it is a girl? ______9_______

d) What is the / chance that their child will ha#e hemophilia if it is a boy? ______59________

0. -ou are gi#en the following *2A3 strand of 42A that is 5666 base pairs long. The sites on the 42A where #ariousrestriction en7ymes will recogni7e and cut are indicated below!

6%%%%%%%%%%%%%%%%%%%%896 (BamH*)%%%%%%%%%%%%%%%1566 (Hind***)%%%%%%"666 (BamH*)%%%%%%%%%%0166 (Hind***)%%%%%%5666

a) How many 42A fragments would result from a BamH* digest? _!__ What would their si7es be? $59, 159, 999

b) How many 42A fragments would result from a Hind*** digest? _!___ What would their si7es be? 1;99, 1!99, "


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b) The brown%eyed female in the


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a) -ou are ased to design a probe to hybridi7e to the following segment of 42A! 9, AT@TA@A@@ 0,What should the se>uence for the probe be? Dont forget to label the 5 and 3 ends of the DNA.

!2 %AGA%G%GG 52

b) As a lab technician& part of your +ob is to mae sure the probes you are using are appropriate for the 42A you aretrying to detect. -ou are woring with the following sample of 42A (only one strand is shown)!

9, AT@@@TAATG@AT@TAAT@TA@A@@T@TA@TTTA@AATATAG@TA@TA@TT@AT@@T@ 0,

i. Suppose you were to cut the 42A shown abo#e with the en7yme HaeIII. The recognition se>uence for thisen7yme is 9, @@ 0,. The en7yme cuts between the and @ bases.*n the strand of 42A abo#e& draw line(s) to show where the en7yme would cut. W

Enzyme cuts between the bolded blue basesii. -ou run the 42A that you ha#e digested with HaeIII on an agarose gel. -ou get the results shown to

the right (the well is on the top of the gel photo)!

iii. -ou denature the 42A from the gel and transfer it onto a nylon membrane. -ou incubate themembrane with the probe you made in part (a). 4raw an arrow to the 42A fragment(s) on the gel thatthe probe will bind to. See arro

i#. The same nylon membrane can be used with another probe. The membrane is sub+ected to high

temperatures to detach the e$isting probe from the membrane. The probe is washed off then themembrane is incubated and hybridi7ed with a new probe. Suppose you incubate the membrane withthe following probe! 0, AT@AA@TA 9,Which 42A fragment(s) will this new probe bind to? @ircle the fragment(s) on the gel that this newprobe will bind to. %&e 0ragment t&at t&e DNA ill bind to ill be 52 %AG%%GA% !2 . ircledin t&e diagram.

8. 3uently used to detect different alleles and genetic mutations. Suppose there is an autosomal geneticdisease called SF2S that is caused by a recessi#e allele (a) of the Dwk7gene. The Dwk7gene has a BamHI restrictionsite on either side of it.

8. 3uently used to detect different alleles and genetic mutations. Suppose there is an autosomal geneticdisease called SF2S that is caused by a recessi#e allele (a) of the Dwk7gene. The Dwk7gene has a BamHI restrictionsite on either side of it.

As a genetic counselor& your +ob is to ad#ise couples about the ris their children might ha#e of de#eloping SF2S. Acouple comes to you and gi#es you the following information!

2either of them has SF2S

The husband had a baby brother who died from SF2S at age 0.

There has ne#er been any incidence of SF2S in the wife,s family.

The allele that causes SF2S can be detected by 3


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a) Based on these results& what is the genotype of the husband? ___AA___

What is the genotype of the wife? ___Aa______

b) *f this couple were to ha#e a child what is the / chance that heshe would ha#e SF2S? __9______Show your wor.

c) What are the chances that a child of this couple will be a carrier for SF2S? ___59_____Show your wor.

d) -ou construct a pedigree for the couple. Dsing the information the couple ga#e you as well as the results of theautoradiograph& fill in the pedigree below with the correct genotype for each family member. -ou do not need to fill in thegenotypes for the couple,s future children.

Yo' can2t 4no t&e i0e2s /arents2 genoty/esneit&er

can be aa b't at least one o0 t&em (or bot&* &as tobe a carrier (Aa*.

e) When you loo at the agarose gel under DE light& this is what you see!

There is a large smear of 42A in e#ery laneI *t,s nothing lie the clear bands you saw in the autoradiograph. Why is this?$plain why the gel and the autoradiograph are so different. (Hint! thin about the probe) %&e gel s&os yo' all o0 t&eDNA. %&e a'toradiogra/& 'ses a s/eci0ic /robe, so it only lig&ts '/ t&e one se>'ence o0 DNA t&at com/lements

t&e /robe.

f) -ou suspect that the mutation that causes SF2S might be a point mutation in which a single nucleotide is mutated inthe Dwk7gene. What is the significance of this mutation? Specifically& how does it allow the 3'ences. %&is one m'tation m'st introd'ce a ne restriction site 0or Bam8). %&is means t&e A allele gets c'tinto only one /iece by Bam8) (since it c'ts on eit&er side o0 t&e gene* and t&e a allele is c't into /ieces (oneit&er side and t&en once in t&e middle. =&en t&e /robe binds, it binds to all o0 t&e A allele b't it only binds tot&e !99 b/ /iece o0 t&e a allele a0ter it is c't.

KEY

male

female

future child

indi#idual with SF2S (shaded)

indi#idual without SF2S (unshaded)

carrier for SF2S

ane 1 G Husband

ane " G Wife

ane 0 G *ndi#idual with SF2S

ane : G Si7e Standard (896& 966& :"9& 066& "66)

Half

shaded

Half shaded


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g) Based on the autoradiograph& how many base pairs long is the Dwk7 gene? __599___ bp

h) A diagram of the a allele of the Dwk7gene is shown below. *ndicate any BamHIrestriction sites on the diagram andshade in the area where the probe binds during the Southern Blot. abel the right side of the diagram as total length ofthe gene.

1 599bp

%&e lines re/resent &ere Bam8) ill c'ts, t&e n'mbers re/resent &ere it ill c't5. 3


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J. As the newest member of San uad& you are assigned a burglary case in which there are 0possible suspects. When the burglar fled the scene of the crime& heshe cut himherself on a broen window and leftbehind some blood. After obtaining a court order to get the 42A of all three suspects& you do 3

genetics problem set 2012

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