On page 150, Moalem describes retroviruses that found a
permanent place in our DNA. They are called human endogenous retroviruses or
HERVs. Moalem says that viruses that do not harm but instead helps, increases
the chances of survival and therefore may become a permanent part of the gene
pool. HERVs relate to Big Idea 3, Living systems store, retrieve, transmit and
respond to information essential to life processes, because HERVs relate to DNA
and the important role it has on an
offspring’s chance to survive and reproduce.
Moalem says that the HERVs play important roles in human
health. What roles of HERVs have been uncovered? What are examples of
retroviruses that have found permanent places in our DNA? How do these
retroviruses help increase our chances of survival? Also, Moalem says that there’s
documented links between HERVs and psoriasis; what is the link/ explain the
connection between HERVs and psoriasis?
(Hervy Ong, hong3@students.d125.org)
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ReplyDelete"What roles of HERVs have been uncovered?"
ReplyDeleteHuman endogenous retroviruses have at least three major roles, which are gene regulation, disease, and evolution. HERVs have acted in gene regulation in areas like the placenta, liver, colon, and other parts of the body. HERVs has also been linked to diseases like psoriasis, cancer, and melanoma. Along with all of these, retroviruses also play a part in evolution like how the way they integrate in hosts can specify common ancestors between two different species as well as natural selection acting upon the a non-harmful virus, allowing it to continue in the cycle of “survive and reproduce”.
"What are examples of retroviruses that have found permanent places in our DNA? How do these retroviruses help increase our chances of survival?"
At least 8% of the human genome contains retroviruses that are here to stay. Some HERVs that we know of are HERV-K, HERV-W, and HERV-L. There is an envelope glycoprotein of HERV-W that is expressed to help create a healthy placenta, which is important in the process of giving birth. HERVs like HERV-W are helpful towards our survival and reproduction and possibly become part of our gene pool with the help of natural selection.
"What is the link/Explain the connection between HERVs and psoriasis?"
There is a HERV gene that may cause increased susceptibility to psoriasis. A protein called HERV-K dUTPase has been found to stimulate production of psoriasis-associated cytokines in immune cells, increasing the chances of fully developing the disease. No definitive relationship has been determined between HERVs and autoimmune diseases yet, but finding HERV-E envelope glycoproteins and HERV-W RNA transcripts in psoriasis patients and not control patients demonstrate some sort of association between the two.
HERVs relate to Big Idea 3 because they affect your DNA and your ability to survive and reproduce, which also affects your offspring and their ability to survive and reproduce. Human endogenous retroviruses are permanent parts of the human transcriptome and therefore are passed down to following generations if not eliminated in the current generation. This follows the idea that changes in DNA cause gene variation, which is nearly always advantageous to the survival and evolution of a species.
Resources: http://jvi.asm.org/content/79/1/341.full
http://www.intechopen.com/books/recent-advances-in-the-biology-therapy-and-management-of-melanoma/the-potential-importance-of-k-type-human-endogenous-retroviral-elements-in-melanoma-biology
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1906363/
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375357/