Assignment 1

Sept. 25, 2018

This assignment is worth 5% of the course grade.

Due: Tue. Oct. 2, 2018.

Chromosomes from human meiotic cells.

1. (1 point) Recalling that the human genome has 23 chromosome pairs, from what stage of meiosis was the cell that is shown in the figure above? Explain your reasoning.

Hint: X and Y chromosomes are labelled. Also keep in mind that on chromosome spreads, chromosomes sometimes overlap one another, depending on how the cells break apart on the slide.

2. (3 points) Three proteins were identified on these chromosomes, using fluorescently-tagged antibodies each specific for one of 3 proteins: the kinetochore protein CREST, SYCP3/SYCP1 proteins from the synaptonemal complex, or the DNA mismatch repair enzyme MLH1.  Each antibody fluoresces in a different colour, either red, yellow or purple.  Using a table similar to the one below, tell which protein corresponds to which fluorescent dye, and explain your rationale for those choices.

fluorescent tag



3. (1 point) Based on your answers to question 2, draw a diagram showing a human autosome (ie. other than X or Y) at diakinesis. Indicate on your diagram where you would expect to see antibody fluroescnce to MLH1, CREST and SYCP3/SYCP1. Use arrows, labels, shading, dots etc. to indicate more clearly where the signals for each of these proteins would be found on chromosomes at diakinesis/metaphaseI.

Submitting your assignment

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Note on grading: In assigning a grade, some consideration may be given to how the answer communicates your ideas. Keep in mind the following:

Note on academic integrity: The results shown in this assignment may be derived from the research literature. It will be considered a breach of academic integrity to search for the paper on the Internet and simply copy the author's conclusions from the paper.

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