Lqb human cell molecular biologyvirgen workshop answer sheetssemester

https://blogs.scientificamerican.com/guest-blog/body-altering-mutations-in-humans-and-flies/

COPYRIGHT – Dr Sally-Anne Stephenson, QUT

https://blogs.scientificamerican.com/guest-blog/body-altering-mutations-in-humans-and-flies/

http://apps.health.qut.edu.au/scb122/QUT%20VirGen/flies/virgen.htm

INSTRUCTIONS

4. If the message is "OK" you can proceed to look at the F1 progeny numbers using the "See the results" link. If not, you will have to modify your selection(s).

5. Click on the link at the bottom to mate the F1 flies and see the F2 progeny numbers. However, if there is more than one phenotype of F1 female, or more than one phenotype of F1 male, you should think about what this means before proceeding.

1. Mate the parent flies

2. note down the F1 phenotypes and numbers

2. outline the segregation of alleles and phenotypes from parents to F2

3. do a chi-square test of your hypothesis on the F2 data

1. Wild type female x Radius Incomplete male

Recessive because F1 (heterozygous) are wild ∴ brown is recessive

4. Model Parents Wild type female x Radius Incomplete male

Gametes + , ri x + , ri

Punnet square

7. χ² is less than 3.84 and F2 ratio is as predicted by model ∴ hypothesis is accepted.

Monohybrid cross number ______2_____

4. Model Parents __Lobe Eyes__ female x __Wild Type___ male

__ __ x __ __

Punnet square

Because this is less than / more than (circle one) the Chi Square statistic value for 1 degree

freedom (3.84) the F2 ratio is / is not (circle one) as predicted by model

2. Hypothesis __ Curved Wing ___ is _______________and __________________

3. Reasoning ____________ because _________________________________________

F1 __ __

F1 cross __ __ x __ __

5. Predict F2 phenotype ratio should be __________ : _____________

6. Chi-square test (computer generated)

is accepted / rejected (circle one).

Monohybrid cross number ______4_______

4. Model Parents ___ Wild type ___ female x __ Tan Body __ male

__ __ x __ __

Punnet square

7. χ² is ____________ .

Because this is less than / more than (circle one) the Chi Square statistic value for 2 degrees of freedom (5.99) the F2 ratio is / is not (circle one) as predicted by model

Can't cross the F1 flies - F1 ratios are wrong for that option

NB

____________ because _________________________________________

4. Model Parents __________ female x ____________ male

Gametes , x ,

Punnet square

__________ : _____________:­­­­­­­­­­__________ : _____________

6. Chi-square test (computer generated)

Monohybrid cross number ______6_______

1. ___Bar Eyes____ female x __Wild type____ male

__ __ x __ __

Gametes x /

Because this is less than / more than (circle one) the Chi Square statistic value for 2 degrees of freedom (5.99) the F2 ratio is / is not (circle one) as predicted by model

∴ the hypothesis that Bar Eyes is _________________ and ________________

NB

1. Dominant OR recessive OR lethal

4. Model Parents _ Wild type__ female x _ Aristapedia Antenna __ male

__ __ x __ __

Punnet square

6. Chi-square test (computer generated)

7. χ² is ____________ .

For each of the crosses listed below:

1. mate the parent flies

1. determine (hypothesise) the mode of inheritance of each mutation (autosomal, sex-linked, dominant, recessive and combinations thereof) and predict the phenotype ratios in the F2

2. outline the segregation of alleles and phenotypes from parents to F2

The crosses are:

1. purple eyes female x spineless bristles male

_________________________________ female x _________________________________ male

Insert tables here

And is ____________ because _________________________________________

Spineless Bristles is ____________ because _________________________________________

F1 __ __ __ __

F1 cross __ __ __ __ x __ __ __ __

_________________ : _________________ : _________________: _____________________

6. Chi-square test (computer generated)

_________________________________ female x _________________________________ male

2. Hypothesis Phenotype 1 __Lobe eyes __ is ______________ and _________________

Vestigial Wing is ____________ because _________________________________________

And is ____________ because _________________________________________

F1 cross __ __ __ __ x __ __ __ __

Gametes

6. Chi-square test (computer generated)

7. χ² is ____________ .

2. Hypothesis Phenotype 1 __White eyes_____ is ______________ and _________________

Phenotype 2 ___black body_ is ______________ and _________________

And is ____________ because _________________________________________

4. Model Parents _____________ female x ______________ male

Gametes

__ __ , __ __ , __ __ , __ __ x __ __ , __ __ , __ __ , __ __

6. Chi-square test (computer generated)

7. χ² is ____________ .

2. Hypothesis Phenotype 1 ___Lobe Eyes____ is ______________ and _________________

Phenotype 2 ___Sable Body_ is ______________ and _________________

And is ____________ because _________________________________________

4. Model Parents _____________ female x ______________ male

Gametes

__ __ , __ __ , __ __ , __ __ x __ __ , __ __ , __ __ , __ __

6. Chi-square test (computer generated)

7. χ² is ____________ .

1. mate the parent flies exactly as shown

2. backcross the F1 females back to the parent male and note down the F2 phenotype numbers

The crosses are:

1. wild type female x eyeless eyes and shaven bristles male

Linkage cross number ______1_______

1. ________________________________ female x _________________________________ male

4. Ratio produced is _______ : _______ : _______ : _______

Hypothetical ratio if not linked is 1 + : 1 EY : 1 SV : 1 EY, SV

8. Map distance = ______cM

9. The genes for _______________ and ______________ are located _______________________

_________________ : _________________ : _________________ : _________________

3. Parental phenotypes are ___________________ and _____________________________

6. _____________ is greater than _______ ∴ does/does not support independent assortment.

Suggests ____________________

Linkage cross number ______3_______

1. ________________________________ female x _________________________________ male

4. Ratio produced is _______ : _______ : _______ : _______

Hypothetical ratio if not linked is 1 + : 1 BW : 1 DP : 1 BW, DP

8. Map distance = ______cM

9. The genes for _______________ and ______________ are located _______________________

_________________ : _________________ : _________________ : _________________

3. Parental phenotypes are ___________________ and _____________________________

6. _____________ is greater than _______ ∴ does/does not support independent assortment.

Suggests ____________________

Working with Drosophila fly crosses is a relatively simple way to demonstrate genetic principles. When dealing with human genetics such analyses are not possible. Even if you could tell people with whom to marry & produce offspring, the wait to see the outcome of each cross would be tedious (especially if the trait only manifested itself in mature individuals!). Furthermore, the number of human offspring is not sufficient for any meaningful statistical analysis (as may be done using Drosophila cross data in VirGen).

Pedigree analysis involves the plotting of family relationships back through as many generations as possible (a.k.a. genealogy). The result is a family tree or pedigree. When members of the family inherit a characteristic phenotype this may also be plotted on the pedigree. These phenotypes may simply be examples of commonly seen variation in human features such as eye colour, widow’s peak or attached earlobe OR they may be pathological disease states.

= male showing trait = female showing trait

Problems: For each pedigree determine (where possible) whether the trait is dominant or recessive and whether it is autosomal or sex linked.

______________________________ _____________________________

______________________________ _____________________________

______________________________ _____________________________

b) III-2 X III-3 ____________________

Problem 3: In this pedigree we know that I-2 is homozygous. With this in mind, is the pedigree displaying a Dominant or recessive trait? a) Is I-1 homozygous or heterozygous? b) What is the probability that the offspring of couple IV-2 and IV-3 will have the trait? c) What is the probability for that the offspring of III-1 and III-2 will have the trait?

c) ______________________________________________

Problem 4: Is the following pedigree displaying a Dominant or recessive trait? What is the probability that the offspring of IV5 will show the trait if she marries a) her boyfriend with the trait OR alternatively b) another boyfriend who is known to be heterozygous, OR c) these two boyfriends fight leaving the field clear for her childhood sweetheart who is homozygous wild type...

(20 marks)