DNA Fingerprints & Blood Groups

NAME:????

• Instructions: Enter your name here: “Joe Bloggs” Read over the case study of Susie Q and answer the

questions that follow, you may make use of any notes or powerpoints.

You will type your answers on the powerpoint itself where there is a textbox/drawing box that allows you to.

Once you have completed all the answers, delete all the slides that have “DELETE SLIDE” on them, save the powerpoint and hand it in for marking.

Imagine you are a forensic scientist when answering the questions.

With many of the ethical questions remember that there is no BLACK or WHITE answers. In fact ethics is all about GREY areas, as long as you substantiate you answers with logic and informative knowledge.

Read the mark scheme to make sure you have not left any points out.

BLACK GREY

These are the days of our lives…

• You are a forensic detective and specialize in child custody cases.

• Susie Q is a 32 year old single mother who is currently unemployed and living financially off her monthly child’s grant and a small savings account which she inherited from her mother. A year ago she fell pregnant again and now has given birth to a baby boy, Tok. Poppers Galore was Susie Q’s boyfriend at the time she fell pregnant, but left her after he suspected that she was seeing his best friend, Johnny B. Goode. Her relationship with Johnny B. Goode was intimate one night after she went to him for help after Poppers Galore came home drunk and hit her. She is determined to know who the father is as she cannot finance two children, and would appreciate some sort of financial support, which she is by law entitled too.

• She proposes her case to you and you accept gladly because you know that both Poppers and Johnny are extremely wealthy businessmen who could easily help support a child.

Evidence No. 1• After questioning the two men, you notice that

they are quite similar in looks, however Johnny has blue eyes and Poppers has brown eyes. You then look up in your records and read that Susie Q has Brown eyes and Tok was born with blue eyes. Recalling back to your matric syllabus you remember that Brown eyes was a dominant trait (B) while blues eyes was a recessive trait (b).

1) Using just this phenotypic evidence explain why one cannot deduce who is likely to be the father, even though Tok and Johnny both have blue eyes. Make use of the monohybrid crosses to help explain your answer (4)

MONOHYBRID CROSSES: = Susie Q = Poppers = Johnny

= Possible Tok’s Fill in genotypes and show

potential crosses

XP1:

F1:

gametes

Evidence No. 1

Fill in information to help you start….

• Brown eyes (B) Blue eyes (b)Genotypes:Tok =Johnny = Susie Q = / Poppers = /

??

??

? ?

??

?? ?? ??

? ?

Evidence No. 1

??

MONOHYBRID CROSSES: = Susie Q = Poppers = Johnny

= Possible Tok’s

XP1:

F1:

gametes

??

??

??

??

??

? ? ? ?

Write your deduction here…

??

Evidence No. 2

• You then decide to do a blood test as you know that blood genes were used as the earliest form of genetic markers. After taking blood from both potential fathers, Susie Q and getting hospital records that show Tok’s blood type, the following genotypes were found: Susie Q (IA/i), Tok (Blood group A), Johnny (IA/i), Poppers (IA/IB).

1) Draw Punnet squares on the next slide to show the potential blood group genotypes of the offspring (click on the ???? to add text). (5)

2) Are you able to come to a conclusion now as to who the father is, why? (2)

3) Looking at the allele frequencies/ phenotypic ratios/percentages who would you say is more likely to be the father, and why? (4)

Evidence No 2.1

???? ????

???? ????

??

??

?? ??

????

????

????

????

??

??

?? ??

***To insert superscript, go to Format – Fonts - superscript

1) Draw Punnet squares on this slide to show the potential blood group genotypes of the offspring (click on the ???? to add text). (5)

Evidence No. 2

2) Answer here…

3) Answer here…

2) Are you able to come to a conclusion now as to who the father is, why? (2)

3) Looking at the allele frequencies/ratios/percentages of the potential offspring would you say is more likely to be the father, and why? (4)

Evidence No. 3• You eventually persuade the SAPS to grant you funding to

have DNA profiles/fingerprints done on all involved in your case. After gaining consent from all parties involved you send blood samples off to the National Forensics Laboratory in Pretoria for DNA profiling using certain genetic markers. Two weeks later the results return and are shown below right:

1) Can you now deduce who the father of Tok is? Who is it? (1)

2) Out of all the procedures taken, which do you think is the most reliable and give two reasons to support your answer? (3)

3) Give advantages and disadvantages of DNA profiling/fingerprinting and using blood groups in paternity testing. (5)

4) Do you think that it is ethical for Susie Q to allow the SAPS to obtain Tok’s DNA profile even though in the long run Tok lives a good life as a result of this case? Give reasons to support your answer? Bullet your answer.(4)

5) “One can never prove paternity, one can only disprove paternity” discuss this statement using scientific thinking. (4)

Evidence No. 31) Answer here…

2) Answer here…

3) Answer here…

Evidence No. 3

4) Answer here…

5) Answer here…

Question

Information Mark

Evidence No.1

1)

Answers correctly using phenotypic evidence and deduction:

Complete deduction and shows monohybrid cross using phenotypic evidence = 4

Shows monohybrid cross from phenotypic evidence but doesn’t deduce answer fully = 3

Partially explains monohybrid cross using phenotypic evidence = 2

Answers incorrectly but attempts monohybrid cross = 1

No answer given= 0

/4

Evidence No.2

1)

Shows understanding of inheritance of blood groups (co-dominance):

Fills in both Punnet squares correctly and writes using correct blood allele nomenclature = 5

Fills in Punnet correctly but blood nomenclature is incorrect = 4

Fills in only one Punnet correctly but partially fills in the other Punnet correctly = 3

Fills in both Punnet squares but with a few mistakes in both = 2

Attempts to fill in Punnets but anwsers incorrectly with no blood group understanding = 1

No attempt in filling in Punnets = 0

/5

2) Writes down correct conclusion and give a reason. /23) Gives name of probable father and explains using allele frequencies/ratios/ percentages. /4

Evidence No.3

1) Correctly identifies the father. /12) Correctly identifies most reliable procedure and gives two valid reasons. /33) Gives a minimum of 5 advantages and disadvantages of DNA profiling and blood typing. /5

4)

Gives an ethical opinion and backs opinion up with 3 valid reasons:

Exceeds critical thinking and substantiates with 3/more valid reasons = 4

Writes opinion and substantiates with two valid reasons = 3

Has opinion and reason substantiates answer = 2

Has opinion but cannot substantiate with a reason = 1

Does not have a realistic opinion and shows no reasoning = 0

/4

5)

Understands statement and explains his understanding using scientific thinking:

Exceeds understanding of statement and uses scientific terminology = 4

Explains statement but does not use scientific terminology= 3

Paritally understands statement and attempts to explain his understanding = 2

Attempts to explain statement but has very little understanding = 1

Does not attempt to explain statement = 0

/4

Added name, followed instructions correctly (deleted slides that needed to be deleted) and worked well under test conditions. /3

TOTAL /35

Name:

Set info:Mark Scheme