The Genetics of Eusocial Insects

The Genetics of Society
Claire Asher and Seirian Sumner
1 January 2015

Link to Article: http://www.the-scientist.com/?articles.view/articleNo/41704/title/The-Genetics-of-Society/
Link to Eusocial Insects explained: http://es.rice.edu/projects/Bios321/eusocial.insect.html

Eusocial insects are recognized by three defining characteristics:
1) The mother conducts care of the young
2) Insects from sterile castes aid the reproducing organism
3) There are overlapping generations. This allows for older generations of offspring to help younger generations.

While Darwin was developing his theory of natural selection, he encountered altruistic insects. Darwin wondered how different behavioral traits were expressed through genes and why some insects were subordinate to others of the same species. He also wondered how a single ancestor led to the development of "social" castes in eusocial insects.

One hypothesis proposed was that a solitary insect lived as a single mother. This mother then laid eggs and foraged for food to feed her offspring. Upon reaching maturity, offspring would forage and reproduce on their own, resulting in the conventional non-eusocial insect. Eusociality developed when offspring remained at the nest with their mother past adulthood. When the mother reproduced again, the first generation of offspring would help their mother raise the newer generation. As the helper insects began to take on specific roles in the nest, the mother, not having to provide food for the new generation, would focus solely on reproduction while the other generations would forage for food and subsequently become workers. The newly evolved phenotype, "the queen", had the exclusive responsibility of reproduction while foraging and laborious behavior was taken on by workers. Thus, creating a eusocial insect society with social castes.
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The hypothesis is supported by the recent discovery of shared genes between "queen" and "worker" insects across all species. These genes have been shown to code for behavioral traits which explains the shared eusocial behavior traits: queens reproduce while workers complete laborious tasks of the nest.

Shared genes are further expressed through phenotypic differences; for example, a queen ant is over 10 times the size of a leaf-cutter ant. Scientists believe that sometime during the evolution of eusocial insects, regulatory elements called microRNAs controlled the genotypes of organisms through gene regulation and protein production and from these genotypes, the ensuing phenotypes. Researchers have concluded that this phenomenon was not entirely a product of natural selection as there are many molecular level happenings that affect the regulation of genes and the production of proteins. However, one reason eusocial insects exist is because the division of labor results in a more efficient society. This is interesting because eusocial societies resemble primitive human societies with the basic division of labor and social hierarchy.

This article relates to both the last unit on molecular biology as well as the current unit on evolution. Through evolution, eusocial insects are prevalent because the micro-societies they created were more efficient than those of other insects. This development might have resulted in more offspring (higher fitness) and led to the social structure becoming widely seen. Additionally, the article relates to molecular biology because it addresses regulatory elements that control gene expression. This ultimately results in different insect social castes.

Snake Evolution happens to have another way

Snake evolution happens to have another way

January 5,2015

http://phys.org/news/2015-01-perspective-snake-evolution.html#jCp

Previously, people thought that snakes have developed from snakes into a more simplified form. But, paleontologists Jason Head and David Polly found out that snakes didn't necessarily evolved from lizards. They have found new ways of how they developed through finding out that that there were distinctions in the snakes vertebral bones and the backbone of the four legged lizards. In the concept of hox genes which govern the boundaries of the neck, trunk, lumbar, sacral and tail regions of limbed animals, they were thought of disrupting the snakes body forms causing them to have no limbs and a simplified structure. But actually, if the hox genes which only control a small part of the gene or else the structures of the snake and lizard would be identical which is not true. Polly said, "It isn't that snakes have lost regions and Hox expression; it is that mammals and birds have independently gained distinct regions by augmenting the ordinary Hox expression shared by early amniotes." This means that it doesn't mean snakes are simplified, its that animals have gained more distinctness in their body which makes it more complex possibly for better adaptation to their environment like better maneuverability and prey catching. Additionally through combining snake vertebrae information with fossils, snake evolution was very unsimilar to what was concluded from developmental genetics alone. Through this study, the direction of how we thought of evoution is opposite of what we have thought as before.

This relates to our current unit in the sense of right now that we are learning about evolution and how many species evolved overtime. Scientists are now beginning to take in new perspectives of how reptiles have evolve based on this scientific study. Originally, it would be thought by us that snakes have evolved from lizards which makes some sense because they are part of the same reptile family. But what is unique is that snakes were discovered to be different from their lizard ancestors unlike birds and mammals which most of them have the same vestigial structures of their ancestors. It very likely could be for the snakes to take in better ability to catch prey or protect themselves from natural disasters or something similar to that. In short, this begins to gain scientists a new perspective on how reptiles and possibly many species evolved over time and why they might change some structures from their ancestors. 

 

Scientists Discover the First Protein That Can Edit Other Proteins

Links: http://www.wired.com/2015/01/grawk-proteins-making-proteins/

Scientists Discover the First Protein That Can Edit Other Proteins
Nick Stockton
1 January 2015

As we learned during our last unit, protein synthesis occurs in ribosomes and is coded for by mRNA. This, however, may not be the only way for proteins to be formed. Recently, scientists have discovered that some specific types of proteins can actually create new polypeptide sequences, without the use of mRNA. One such protein is Rqc2. Rqc2 is a protein involved in a recycling process that takes place when an error happens in translation. When such an error occurs, the ribosome essentially stalls and is unusable, until a group of proteins come in and break apart the ribsome, mRNA, and the partially made protein. Rqc2's role in this clean-up process is to attach a random sequence of the amino acids threonine and alanine to the partially made protein before it is recycled. This newly added sequence will not fix the ribosome, or complete the protein. It will instead act as a signal to other destructive proteins to take the faulty one apart. What is surprising about this process is that a protein, not mRNA, decides which amino acids will be added.
 Diseases such as Alzheimer's, Huntington's, and Lou Gehrig's are caused by defective quality control proteins. Knowing the exact conditions that trigger Rqc2 could help lead to new treatments for such
conditions.

This article directly relates to our last unit on molecular biology. Although the article describes a different process than we discussed in class, it is still about protein synthesis, which was an important part of our last topic.

Stem Cells Engineered

http://www.ibtimes.co.uk/stem-cells-engineered-using-genome-editing-technology-1482233

This article, by Jayalakshmi K., discusses expanding genome technologies for engineering stem cells. Scientists are hoping for treatments for diseases and to be applied in new/improved medications. Certain methods, such as CRISPR and TALEN can modify DNA by adding, taking away, substituting, or shortening DNA’s gene sequences. However, there is now a new technique (named iPCS) developed at John Hopkins that causes adult cells to preform similar to embryonic stem cells. This allows the adult cells to evolve into certain needed cells. To perform this new technique, the genome editing process uses DNA and RNA bound together by an enzyme to allow scientists to know where to modify.

This article relates to what we have been learning in class about genetic modification and the process taken to insert the desired genes and change DNA sequences. Though the process used in this case is different from the techniques we have studied, scientists edit the DNA sequence to produce the organism with the wanted additional traits in both. We have also studied stem cells; mostly found in the embryo, the cells are able to develop into other cells (Campbell, Neil A., Brad Williamson, and Robin J. Heyden. Biology: Exploring Life). Adults have few stem cells that can make limited new materials (such as tissues), so the development of iPCS will further expand and improve health.

K., Jayalakshmi. "Stem Cells Engineered Using Genome Editing Technology."                       International Business Times RSS. N.p., 7 Jan. 2015. Web. 08 Jan. 2015.

Most Cancers Due to Bad Luck, Not Heredity or Lifestyle

Title: Most Cancers Due to Bad Luck, Not Heredity or Lifestyle
Author: Kevin Mayor
Published: 2 January 2015
Source: http://www.genengnews.com/gen-news-highlights/most-cancers-due-to-bad-luck-not-heredity-or-lifestyle/81250759/

Cancers are all caused by environment, heredity, and bad luck. However, most people with cancer are just unlucky. Cancer is caused by a mutation in DNA. The lifestyle and heredity of a person only influence the probability of the mutation and not the disease itself. Using tobacco and exposure to radiation only add the "bad luck" factor. DNA mutations are completely random. As a result, more resources should be focused on detecting cancer at an early stage. This is the most effective way to eradicate cancer.

This article relates to "Inherited" Cancer. The article says that cancer most likely won't be inherited from a parent. This is because the mutations passed onto children will only increase the risk of cancer. If a child receives a mutation, they will not necessarily develop cancer. Cancer is caused by mutations in DNA and influenced by genes and other mutagens. 

Why are Most of us right handed?

Link:  http://www.bbc.com/future/story/20141215-why-are-most-of-us-right-handed
 by Jason G. Goldman BBC
Published: December 16, 2014

Summary:
Around 85% of humans have a right hand dominance over left handedness, in no instances is left-handedness more prevalent than right handedness. A bias of one side chosen over the other in the use of our limbs begins in the brain, with the left hemisphere controlling the right side of the body, where most large tasks are controlled. The division of neurological labor over hemispheres of the brain is a feature that evolved in most animals over time as a way to carry out multiple tasks at the same time. For instance, it is possible that the left hemisphere became responsible through evolution to carry out routine tasks, such as foraging for food and react to changes in the environment. It has been suggested that when homo sapiens evolved to stand on two legs, their hands became free to develop different sets of skills, resulting in a "strengthening asymmetry" for using tools and performing tasks. This is supported by the fact that when chimps stand on all fours, they show no hand preference. Also, stone tools made 1.5 million years ago, show species wide right-handedness.

This article connects directly to the study of evolution and certain traits evolving to become dominant over others as species adapt to their environment. As human evolution progressed, we began to stand on two legs, which freed up our hands for specified tasks. Through this evolutionary trait, the dominance of one hand over the other evolved in a clear pattern of right-handedness over left-handedness. This particular trait is very interesting because the evolution of the trait is mostly unknown because left-handedness has been shown to not be a drawback in an individuals ability to function. This brings up the question of why right hand dominance has emerged to be much more prevalent than left hand dominance.

Scientists Discover New Mechanism of Protein Synthesis

Scientists Discover New Mechanism of Protein Synthesis
by Sci-News.com

Published: Jan 4, 2015

http://www.sci-news.com/biology/science-new-mechanism-protein-synthesis-02381.html

Summary by Alice Zorn

A group of researchers from Stanford University and University of California discovered that amino acids can be assembled without "blueprints" (DNA and mRNA). The scientists said that the "ribosomes are machines on a protein assembly line, linking together amino acids in an order specified by the genetic code. When something goes wrong the ribosome can stall, and a quality control crew is summoned to the site," the ribosome is then disassembled in order to "clean up the mess" and the blueprint is discarded. The partially-made protein, however, is recycled, and this new study discovered that just before the protein is recycled, Rqc2 (a protein conserved from yeast to man) makes the ribosome add alanine and threonine (two amino acids) repeatedly, and randomly. This new protein might not be what it was intended to be, but it may have a code that signals that it must be destroyed.



This new discovery relates directly to our studies of molecular genetics. During that unit we learned how protein synthesizes with the help of mRNA and the genetic code, and this new information will further our understanding of the importance of ribosomes in the process, and the difference between successful synthesis and unsuccessful synthesis. This study also shows how much biologists still have to learn about biology, and how science is always changing.