OK, gang, help me out here. I’m swamped today — my morning is destroyed because I have to go in to the clinic for my annual thorough extensive physical check-up, and I get out just in time for my afternoon class, and then I’m free, sort of. Except that I have to compose a 10 question online quiz on chromosome variations.
So give me some good questions on deletions, duplications, inversions, and translocations. Preferably questions that can be easily machine-scored, but I do throw in an essay question or two.
Get to work. I’ll expect them in the comments section here when I get back at 1:30.
Don’t disappoint me.
Maybe too easy:
What explains the difference in the number of chromosomes between H. Sapiens (46) and other simians (e.g. the 48 of Pan troglodytes)? What evidence supports supports this?
Assuming that Cheez-Whiz is derived from “Cheez”, and Cheez is a mutant strain of actual Cheese, how would the original Cheese’s chromosomes differ from the final product?
Support your conclusion with peer-reviewed citations (or lots of exclamation points).
How does trisomy 21 happen in 95% of cases ?
a) Meiotic Nondisjunction (95% of cases): The egg or sperm cell retains both copies of chromosome 21 instead of one, resulting in a zygote with three copies.
this one seems a bit basic. I probably could have done better but I’m tired.
What is the sound of one endonuclease clipping?
In de la Chapelle syndrome, SRY translocates from the y chromosome onto the X chromosome in meiosis prior to the formation of a genetically XX zygote. These individuals are usually:
a) Phenotypically female due to XX karyotype
b) Phenotypically female due to downstream development of the Mullerian ducts
c) Phenotypically male due to SRY activation of SOX9
d) Phenotypically male due to downstream development of the Mullerian ducts
A rather short gene has the following sequence:
TACGAGTAAATT
If the first C is deleted, which of the following is most likely to occur:
a) the gene is never transcribed due to destruction of its promoter sequence
b) the transcript is never translated due to destruction of the start codon
c) the initial methionine is changed to an isoleucine
d) all peptides in the protein are altered due to frame shifting
MECP2 is a gene involved in methylation which can cause developmental abnormalities when disturbed. A phenotypically normal proband is found by genetic testing to have heterozygous X chromosomes with MECP2 duplication on one and normal MECP2 on the other. If she has children with a phenotypically normal mate, you would expect which of the following outcomes:
a) 50/50 phenotypically normal and abnormal offspring
b) all normal offspring because of the phenotypically normal mate
c) all XX offspring are abnormal and most XY offspring are normal
d) all XY offspring are abnormal and most XX offspring are normal
Sorry, correct C and D from comment 7 to
50% of XX offspring are abnormal and most XY offspring are normal
And
50% of XY offspring are abnormal and most XX offspring are normal
Explain some of the most common causes of chromosomal translocations.
Explain, in your own words, what deletions, duplications, inversions, and translocations are as applied to chromosones.
“This country elected Donald Trump as President twice – what’s the point of anything anymore?”
If your genes are XL and you’re only getting half as much exercise as you used to be able to do, determine long will it be before your genes will be XXL.
What?
[Hit the preview button first, Woods, you bloody idiot.]
Do you cover using translocations to construct balancer chromosomes for maintaining recessive lethals?
Q: You have discovered a mutation that causes sterility in D. melanogaster. What are the characteristics of the homologous chromosome necessary to maintain it as a heterozygous strain?
A: Inversion to supress meiotic recombination. Dominant marker to identify any recombinants. Recessive lethal to eliminate homozygotes.
For a longer question, you could ask them how to first design a forward screen for lethals.
Well, if you don’t mind drawing lots of pictures and having them choose among them, maybe imagine a translocation, then have it pair with two normal chromosomes, ask them which of these pictures shows how they will pair at 1st division of meiosis, and then ask them what products result if there is no crossover, or a crossover between the centromere and the breakpoint. Problem with this set of questions is (a) all the drawing by you, (b) if they get confused on the pairing part they might not know what’s going on after that.
Can duplication happen during the “synapsis” phase of Meiosis? (yes/no)
Apparently the phase is called “prophase I”.
In order for an inversion to happen during crossover, how many of the two involved chromosome strands usually has the shape of a loop? (0/1/2)
…at the place where the inversion occurs?
My geneticist wife says you should ask them:
1) What are low copy repeats and what is their relevance for copy number variations.
2) An oocyte is fertilized by a sperm with an isodicentric Y chromosome, name some possible outcomes
#5 & #7 maybe.
#10: that’s just cheating, rephrasing my general question.
#14: Yeah, I’ve got a problem in there about using inversions to suppress crossing over.
#15: this is an online quiz, so no drawing! There’s a written exam coming up in a few weeks. If I were cruel I’d ask them to draw all the gametes produced by a 3-strand double crossover in an inversion heterozygote.
OK, I got it all done, and am salting away a few ideas for the final now.
Off topic but Integrity now re-entering atmosphere heading for splashdown :
Does your assessment software allow for Extended Match questions? If so, I thoroughly recommend them as ways of testing knowledge more effectively than standard multi-choice questions, and you can generate a lot of questions for the same answer set so it’s time-efficient. For example…
For the following questions, the answer key is:
A. Silent mutation
B. Nonsense mutation
C. Missense mutation
D. Insertion or deletion mutation
E. Duplication mutation
F. Frameshift mutation
G. Repeat expansion
Question 1. What type of mutation is TTC -> TTT?
Answer: A
You can pitch the question at the level you want to test. I wouldn’t use the example above unless memorising the genetic code was an essential part of the course, because you can’t identify silent mutations without that knowledge in your head (unless you allow open book). Conversely, some of the options (e.g. insertion/deletion) would be obvious even to a student with limited knowledge. Also, some of those options overlap so the question writer has to be very precise and clear, or leave the options in as distractors and not use any of them as answers.
But you can ask questions that delve deeper, such as…
Q. Which type of mutation would change an amino acid sequence Ser-Pro-Val-Tyr to Ser-Ala-Leu-Leu?
A. Frameshift
Q. Which type of mutation would change an amino acid sequence Ser-Pro-Val-Tyr to Ser-Pro-STOP?
A. Nonsense
Neither of these questions require memorising the genetic code, but they do require understanding of the principles.
Hmm. I just realised that frameshift question is no good — it could be a multi-codon insertion or deletion. Reworded:
Q. Which type of single-base pair mutation would change the amino acid sequence Ser-Pro-Val-Tyr to Ser-Ala-Leu-Leu?
A. Frameshift
Perhaps a silly question but what’s the importance of the de-oxygenation of Deoxyribonuclaeic (spelling?) acid and what happens to that oxygen and what would happen if the oxygen was there? Presumably having oxygen would make it (oxy?)ribonucleaic acid which also seems to work well and from what I gather could’ve been a precursor to DNA yeah?
Might be more a biochemistry than a genetics question but then I guess genetics is a subset of biochem anyhow.
FWIW. I’m definitely well out of my jurisdiction and fields of expertise here – genetics is not a topic I know that much about at all.
Lab coat PZ, where was your lab coat?
@StevoR #25, I was curious about this as well as I vaguely remember reading about what all differentiated DNA from RNA, so did a quick search on the differences. Found this article: https://www.technologynetworks.com/genomics/articles/what-are-the-key-differences-between-dna-and-rna-296719#D2 with the following:
Take that source for what it is worth (I did not validate its veracity) so if any other commenter with more of a Genetics and/or Biology background wants to verify it or provide a better source, that’d be great :) I gotta get back to watching lectures now :P