On pgs 162-163, Dr. Moalem explains how epigenetics plays a role
in birth defects. The earlier epigenetic signals are transmitted, the more
significant the potential changes are in the fetus. So scientists have
discovered that the most critical period are the few first days after
conception. For example, if a newly pregnant mother spends the first weeks of
her pregnancy eating junk food, the embryo may receive signals that its going
to be born into a harsh environment where critical food types are scarce. In
response, certain genes are turned on and off and the baby is born small to
compensate for the lack of food it needs to survive. This relates to Big Idea 4:
Biological systems interact, and these systems and their interactions possess
complex properties. There is an interaction between the environment (what the
mother is consuming) and the living organism (the fetus), which results in the
movement of matter (epigenetic signals).
The Barker Hypothesis is an example phenotype is the physical
expression of your genotype.
Using pgs 162-163, explain his hypothesis correlates with
epigenetics and birth defects. Also, using information from earlier units and
pgs 162-163, explain why the first days after conception are most imperative.
Finally, name some of the implications of epigenetics using pgs 162-163 and
furthering research online
Submitted by Josh Baker (jbaker3@students.d125.org)
On page 162-163 Dr. Sharon Moalem describes the process of a predictive adaptive response. In this response, an organism’s phenotype is affected based on what the mother does during pregnancy. Dr. Moalem describes the Baker Hypothesis, which first suggested a link between poor fetal nutrition and later obesity. To understand the Baker Hypothesis, one must know the difference between a phenotype and a genotype. The phenotype is the physical expression of the genotype – detached earlobes are the phenotype while the DNA pattern would be the genotype. Now, the Baker Hypothesis proposes the idea that your phenotype can change but the genotype would remain the same. Thus, making it possible for the trait of a particular gene to be passed on to offspring even if it isn’t expressed in you. The epigenetics involved in this theory are what influence your phenotype. They don’t change the genotype as the gene is either turned on or off, meaning that the operon cannot transcribe the DNA to make mRNA. In epigenetics something may block the operon so RNA polymerase II cannot continue on with transcription. Therefore, if transcription does not occur, a phenotype may not be expressed, but the genotype is still not affected. This relates to Barkers Theory as David Parker concluded that the weight of a baby is influenced by the amount of nutrition the mother gets. Eventually, the baby may develop coronary heart disease because of its thrifty metabolism-which developed from living in a womb without much nutrition.
ReplyDeletehttp://www.thebarkertheory.org/science.php
The first days after conception are most imperative as the baby may either survive or die in the new environment. The epigenetics involved during the womb stage of the organism may produce a phenotype that fits the environment that the mother makes for the child. However, a baby with a thrifty metabolism, which is born into a family with abundant food, may get fat. It is important in other organisms as well as it relates to the evolution unit. After an organism is first placed in its environment it begins to learn how it must use the characteristics it has based on observations from the mother. The first days are so important because it determines whether or not the specie will survive and it determines how the specie will live.
Some implications of epigenetics are the possibility to rewrite human DNA. If this is possible, we can invent a magic marker to express genes that would best suit our environment. Epigenetics has the potential to give us complete control over our phenotype. According to a journal article from the Tel-Aviv University Medical School, epigenetics can also influence the way two organisms interact. Outside of shifting our own body, epigenetics study can possibly lead to relations between two different uni-cellular organisms. This relates to Big Idea 4, as the epigenetics study can result in biological interactions between two different organisms. Also, the biological make up of an organism is affected by some molecules, which may inhibit transcription. Thus the interactions between molecules and operons change the structure of an organism and change the Phenotype.
Rahul Kosgi (rkosgi4@students.d125.org)