Tuesday, March 1, 2016

In DNA, Clues to the Cheetah’s Speed and Hurdles

In DNA, Clues to the Cheetah’s Speed and Hurdles

This article discussed the studies performed on cheetahs, determining their history and giving some hints as to “how the big cats became the world’s fastest land animals.” These studies were conducted by scientists at the Cheetah Conservation Fund in Namibia, on a cheetah rescued when it was a ten day old orphan, Chewbaaka. Later, more studies were done by scientists at the Theodosius Dobzhansky Center for Genome Bioinformatics at St. Petersburg State University in Russia, who collaborated with BGI-Shenzhen in China and the Cheetah Conservation Fund to analyze the entire genome of the species. After genetic analysis, scientists discovered that the cheetah has less than 5 percent of the genomic diversity (determined by variation in enzyme genes inherited by an animal’s two parents and is critical to its healthy reproduction and immunity to disease) of other wild cats, a level much lower than even inbred domestic dogs and cats and the lowest among the 30 mammals whose genomes have been sequenced. This therefore led to the scientists beginning to think that the cheetah was genetically monotonous several decades ago. These scientists in Russia then figured out the specific underpinnings of the cheetah’s genetic impoverishment and glimpsed the evolutionary chain of events that produced its unparalleled running speed. It was found that there were two specific points in history in which the genetic diversity of the cheetah was reduced. One of these instances was when the population bottlenecks were formed after cheetahs crossed the Bering strait into Asia. The other was late in the Pleistocene epoch when a global extinction event caused cheetah populations to crash. They examined how natural selection affected the cheetahs, firstly that the sequencing of the genome illuminated gene mutations that probably explain the sperm abnormalities seen in all cheetahs today, for they had the gene AKAP4, which likely block sperm development. The second effect natural selection had on the cheetahs, a positive effect, was their running ability. Eleven different genes showed evidence of mutations occurring over generations that boosted the animal’s muscle contraction, stress response and regulation of energy-releasing processes, which improved the cheetah’s running ability.

This article is important to society today because it discusses the possible extinction of yet another animal that played a large role in the world. The article shows the difficulty for the cheetahs to repopulate or enlarge their population because of the disadvantages they have in the field of reproducing, like having the sperm development blocking gene. This article is also relevant to us considering we previously studied genes and how a specific gene can result in traits or diseases passed down, which can also be seen in the cheetahs, which went through much interbreeding to keep the species from decreasing even more in population.

One strength of this article was how it went into depth explaining some of the genes and gene mutations that the cheetahs experienced, explaining some specific examples of traits in the cheetahs the scientists found. Although the article had many strengths, I still feel a few things could have been improved upon. For example, the article did not include much regarding the actual process undergone by the scientists performing the study, for it just gave a general overview of it. I would have liked if maybe it included more about this specific process undergone by the scientists, and not just the broad description of it.

Moffet, Barbara S. "In DNA, Clues to the Cheetah’s Speed and Hurdles." The New York Times. The New York Times, 29 Feb. 2016. Web. 01 Mar. 2016. <http://www.nytimes.com/2016/03/01/science/in-dna-clues-to-the-cheetahs-speed-and-hurdles.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science®ion=rank&module=package&version=highlights&contentPlacement=8&pgtype=sectionfront>.

2 comments:

  1. Moffet, Barbara S. "In DNA, Clues to the Cheetah’s Speed and Hurdles." The New York Times. The New York Times, 29 Feb. 2016. Web. 01 Mar. 2016. .

    John’s summary demonstrates a clear understanding of his topic. It was well-written and covered a lot from his article. He also provided us with a great example of the importance of phylogenetic trees based on DNA sequencing rather than just morphology; he stated the “the cheetah has less than 5 percent of the genomic diversity...of other wildcats,” which one most likely never would have guessed if they hadn’t studied their genome. I also liked how he related the article specifically to our class--it makes us think about how our learning connects to current events.
    There wasn’t much to critique on in this review. I did think that there could have been less details in the summary, and that he could have elaborated more in the second paragraph. If he had talked about the importance of the specific relationship between the two natural events that occurred to cause consequent mutations, as this type of relationship is fundamental to the study of evolution. I would have had a better understanding of how that worked because, to me, it was a bit unclear in the summary.
    I find it fascinating that scientists can come to such specific conclusions about animals and their history by “simply” studying genetics. John included that “Eleven different genes showed evidence of mutations occurring over generations that boosted the animal’s muscle contraction, stress response and regulation of energy-releasing processes, which improved the cheetah’s running ability.” This pattern of thinking not only provides us with more information about science but also empowers other fellow scientists to emphasize their studies on similar topics, which ultimately begets more knowledge.

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  2. Great job John! I loved your summary of the article and was able to learn a lot through your description. It was very interesting to read as well. I also think that your third paragraph, where you talked about the author’s writing overall, was well done. It was clear to me that you closely focused in on what the author did nicely, but also what didn’t work well for you.Finally, I think that the review flowed very nicely and illustrated a great outline of the article. The separation of these thoughts into paragraphs allowed me to clearly understand your review.
    As your review was written beautifully and was well organized, there are a few things I suggest including in your next current event. In your second paragraph, the one that described the importance of the discovery on science, I feel that you could have been more descriptive. Though I was able to understand your ideas, it could’ve included more information. I also think that in your summary paragraph, an explanation of the quote can be added to give a better background of the article to the reader.
    It is interesting to see that scientists believe that the cheetah was genetically monotonous only several decades ago. As that really isn’t far off from 2016, it gives me an idea of what has changed in our life cycle and what has caused these genetic changes over the years.

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