Sex Differentiation in Amami Spiny Rats

In mammals, the presence of the Y chromosome during embryonic development decides whether its offspring will be male or female. Although that is usually the case in mammals, The Amami spiny rat is something extraordinary for they lack Y chromosomes and Sry genes. The Sry gene—Sex-determining Region Y—is located on the short branch of the Y chromosome which initiates the embryonic development of males. In male Amami spiny rats, they only have one X chromosome, while females have both XX.

           

            To understand the gene expression differences in female and male, Cheryl Rosenfeld collaborated with Asato Kuroiwa from Hokkaido University Takamichi Jogahara of the Frontier Science Research Center in Japan, and Scott Givan, associate director of the MU Informatics Research Core Facility to experiment on brain activity of Amami spiny rats. They collected brain samples were collected and RNA was sequenced to compare. Male encoded for various zinc finger protein genes which could be what balanced the loss of SRY genes. The gonad then progressed as testes as a way to help program the brain to be a male. The absence of zinc finger protein led to the development of female. By turning on all the zinc finger proteins this stimulates the differentiation in the sexes.

            Animals that are not mammals have different sex-determination than humans. I think people are so focused and interested in learning about the SRY genes that people tend to overlook that there are other contributing factors in the determination of sexes. By researching more on unexplained sexes with the absences of the Y chromosome, we can fully go in depth on how gonadal and brain sexual differentiation works for different animals.

Heavily Drinking In Teenage Years Can Affect Brain Function of Future Offspring

Loyola University Chicago Stritch School of Medicine performed a study pertaining to binge drinking in teenagers. The main purpose of this study was to explain that binge drinking in teenage years can massively affect the brain function of future offspring. The study determined that teenage binge drinking can change the on-off switches of various genes in the brains of offspring. Constantly binge drinking during teenage years can alter the brain functions of future offspring. This can potentially put offspring at a high risk for depression, anxiety, and metabolic disorders.

An experiment was performed using  adolescent male and female rats that were exposed to large amounts of alcohol comparable to seven binge drinking episodes. After they became sober, the rats mated and the females continued to remain sober as they were pregnant. The rats that were exposed to alcohol were compared to a group of rats that were not exposed to alcohol. Researchers examined the offspring of the rats that were exposed to alcohol and look at the genes in their hypothalamus. The hypothalamus is a part of the brain which is involved in many functions, such as reproduction, stress response, intake of food, and the sleep cycle. Researchers examined molecular changes in the DNA that reversed the on-off switches in individual genes. The results showed 159 changes in the of binge-drinking mother's offspring, 93 changes in binge-drinking father's offspring, and 244 gene changes in the offspring of both binge-drinking parents. 

This particular study is the first of many that prove teenage binge drinking by either parent can cause many alterations in the nervous system of potential offspring. Although the findings of an animal model may not primarily translate to human, there are various similarities between the animal used for the study and human, such as metabolism of alcohol, the way the hypothalamus functions and the pattern and amount of alcohol ingested. I believe that people do not know what the long term consequences of binge drinking are. We should do a better job making people aware because it is hurting the further generations and it is not fair to those children. Innocent children should not have to suffer because of their parents poor decisions regarding drinking, binge drinking does not make anything better, in fact it just makes things worse, long term and short term.

How the Brown Rat Conquered New York

Rats are known to contaminate the places that they inhabit with feces and urine in addition to viruses and bacteria. In many ecosystems they even threaten other species with extinction. They have managed to inhabit wherever humans have. Dr. Munshi-South, a biologist at Fordham University and his colleagues conducted an in-depth genetic study on brown rats after they posed to question “What is a New York rat?” They found that once brown rats settle into a new city, they repel newcomers.

            In order to conduct the study, the team contacted researchers from all over the world in order to compare DNA of rats from around the world to rats in New York. They ended up analyzing the DNA samples of 314 brown rats from thirty countries; from this data, they were able to conclude that different population of rats mixed together over time in order to produce the brown rat. They found that brown rats originated in northern China or Magnolia even though it was previously believed that the brown rat originated in Norway. Farming societies and widespread trade became more and more popular and rats began to migrate, which gave rise to the rats that we know now.

            A biologist at Rice University, Michael Kohn, said that that the brown rats are territorial, so it is hard for other types to get in. Many of the rats that he and his team examined were missing eyes, tails, and had scars that looked like they had been in a brutal fight. He said that this is most likely why we do not see many different kinds of rats in that area. I used to live in New York and now that I am thinking about it, all of the rats that you see in subways, all did look the same. It is cool though that the rats are so territorial that they do not let other types of rats into the city.