On page
167, Dr. Moalem states that traits acquired by parents or grandparents can
be inherited by their offspring for generations, leading to evolution. This discovery relates with Big Idea 1: The process of evolution drives the diversity
and unity of life.
Provide a
specific acquired trait that can be inherited for generations. For the offspring, precisely when is this
acquired trait a selective advantage and when is it not? If this acquired trait is beneficial during the offspring’s lives,
what actions can ancestors take to keep passing this acquired trait? On the other hand, if this acquired trait is
not beneficial during the offspring’s
lives, what actions can ancestors take to stop passing this acquired
trait?
Ken Saito
(ksaito4@students.d125.org)
As stated in Chapter 7, Dr. Moalem mentions how women who were pregnant during the Dutch famine gave, “gave birth to small babies who grew up to be more prone to obesity, coronary disease, and a variety of cancers” (167). This was then proven to be inherited for generations as even the grandchildren 20 years later were prone to the same health defects due to low birth weights and poor nutrition. In this case, this acquired trait is a selective disadvantage as the health defects can decrease the offspring’s lifespan. This along with other lifestyle obstacles may prevent the offspring from ultimately surviving and reproducing, therefore preventing the offspring from passing down their genes. Therefore there aren’t many cases in which this is a selective advantage unless the offspring is fortunate enough to be raised in an ideal environment with the proper nutrition. However, one such case could be that holding off on the gene could actually prove to be beneficial as the gene is held onto a gene until a specific threat occurs within the body.
ReplyDeleteGiven the fact that epigenetic scholars believe this mostly unfavorable trait is therefore passed down through epigenetics, this gives the unfavorable trait the ability to continue to be present regardless of being favorable or unfavorable. Therefore, these traits can still survive from generation to generation, allowing them to be a part of the process of evolution driving the diversity and unity discussed in Big Idea 1. In fact, this can lead to even more diversity as in addition to the favorable traits being passed down to different species, even the unfavorable ones tagged through epigenetics also provide the opportunity for diversity within another species. An example would be that following the normal idea of surviving and reproducing, healthy mothers are prone to give birth to babies that are well-nourished while babies that receive the epigenetic “tag” from the methyl marker differ from these babies as they are now born with low birth rates. Regardless of if this is beneficial for the offspring or not, it still portrays diversity and can explain the reason that we see such diseases today.
Since this trait isn’t beneficial for the most part, what can be done to prevent such a trait from being passed down? Well, according to a research done by doctors at the Howard Hughes Medical Center, for now there are no therapeutic implications just yet. However, as stated before, they did provide data RNAi was in fact prevalent throughout the animal kingdom (including in humans), therefore strengthening support in the role of epigenetics with this trait. After conducting a previous experiment on worms, they hope to find more information on preventing such “tags” from being passed down. They plan on doing so by replicating the Dutch famine stated in the chapter by starving the worms and see whether, as a result of starvation, we see small RNAs being generated and passed to the next generation.
http://www.sciencedaily.com/releases/2011/12/111205102713.htm
(Lois Kim, lokim3@students.d125.org)