2. Assignment Instructions
– 350 words total
– Claim (1-2 sentences), Evidence (1 paragraph), Explanation (1 paragraph)
– Examine all parts of the figure provided below on page 3
Please pay attention to rubric and instructions for maximize the grades.
Good Developing Not sufficient
2 1 0
1 0.5 0
Included where needed and with
Error(s) in format/usage (e.g. not
enough citations) Many errors in format/usage OR missing
Clear logical flow of ideas that is
easy to follow from start to finish Some parts unclear or hard to follow
Many instances where writing was
unclear and hard to follow
Little to no grammar or sentence
structure mistakes, no spelling
Some grammar, sentence structure, or
Multiple of grammar, sentence structure,
or spelling errors
◻ Missing much or all of the
necessary data to support
claim(s)/includign far too much
◻ Includes most of the necessary
data to support claim(s) OR includes
all relevant data + some irrelevant
Clarity of writing 1
Clarity of writing 2
Accurate ◻ Incorrect explanation, reasoning is
irrelevant to the data and/or claim
◻ Some inaccuracies in the
◻ Correctly connects data and
claim using logical explanations of
Complete ◻ Reasoning is insufficient or
◻ Some reasoning missing (e.g.
some evidence not justified)
◻ Includes all the necessary
reasoning to support claim(s)
◻ Some possible claims are
◻ Includes all claims possible &
relevant from the given data
◻ Includes all necessary data to
support claim(s), and not
Missing or extremely incomplete
connect evidence to the
underlying biology/genetics to
explain or hypothesize about
why these results exist. Connect
to claim and broader research
Citations & references
Accurate ◻ Inaccurate description of the data◻ Some inaccuracies ◻ Descriptions of the evidence
◻ No, the claim(s) does not fit the
data/does not answer research
◻ Some of the claim(s) fits the
data/answers the research question.
◻ All of the claim(s) fit the data
and answer the research
Bumwon Kwak (Brandon)
29 October 2017
Writing Assignment # 2
Claim: The cohesion protein REC8 is involved in sister chromatid cohesion and aneuploidy in young versus old oocytes.
Evidence: Aneuploidy is known to often result from chromosome misalignment at metaphases stages. From Fig. B, REC8 intensity is significantly decreased in old age. The deteriorated chromosome cohesion is a leading source of aneuploidy in oocytes in a natural aging mice model. In Fig. F, the interkinetochore distant apart, this happening at Metaphase I and II, showing decreased centromere cohesion. The levels of the meiotic cohesin protein REC8 are harshly decreased on chromosomes in oocytes from old (Jessberger, 2012).
Explanation: There is association among REC8, sister chromatid cohesion, and aneuploidy in young and old oocytes. In Fig. G, Oocytes show increased chromosome misalignment with age, as opposed to when oocytes have reduced misalignment to when young. Oocytes coming from young and aged SAM (senescence-accelerated mice) exhibit centromere linked protein-E (CENP-E) at centromeres of all chromosomes, comprising misaligned chromosomes from aged SAM. Oocytes are prone chromosome mis-segregation, and aneuploidy intensifies with age. As oocyte age surges sister chromatid cohesion is weakened or lost. Cohesion weakening seems to contribute considerably to age-dependent aneuploidy (Garcia-Cruz, 2010). Cohesion defects caused aneuploidies is showed through chromosome segregation dynamics at Anaphase I in live oocytes and counted chromosomes in the subsequent Metaphase II eggs. Age-related aneuploidies are due to weakened centromere cohesion. In conclusion, maternal age-associated upsurge in aneuploidy is habitually due to a failure to efficiently substitute cohesion proteins that are lost from chromosomes during aging.
Garcia-Cruz, R., Brieno, M. A., Roig, I., Grossmann, M., Velilla, E., Pujol, A., … & Garcia Caldes, M. (2010). Dynamics of cohesin proteins REC8, STAG3, SMC1 β and SMC3 are consistent with a role in sister chromatid cohesion during meiosis in human oocytes. Human reproduction, 25(9), 2316-2327.
Jessberger, R. (2012). Age‐related aneuploidy through cohesion exhaustion. EMBO reports, 13(6), 539-546.