Information Concerning X Chromosomes Mechanism - Essay Example

“Seeing X Chromosomes in a New Light” Main Points Introduction Background Information on X- Chromosome 2. Effects of X-Chromosomes in females Using stem cells in treatment procedures Genome diversity Back-up in case of a defective gene Risk of Cancer 3. Effects of X-Chromosome in males Genetic disorder 4. Understanding deactivation of the X-Chromosomes Analysis of the study conducted by Susumu Ohno Analysis of the mice experiment conducted by Mary Lyon 5. Experiment to understand the deactivation of X-Chromosome Done by Dr. Jeremy Nathans and his colleagues Gene Silencing Shutting and waking of Xist molecule Conclusion Importance of solving the X-chromosome mystery References Reason for Using the Article The article relays information concerning X chromosomes’ mechanism and their intricate nature that lead to male or female in human beings, which seems a mystery to numerous people to date. Introduction Hermann Honking named the X chromosome in 1981 as he carried out his experiments (“The New York Times”). This was after he realized that all chromosomes came out in pairs except one hence; he named it the X element. Today, the X chromosome is the determinant of sex. Once an egg takes up X chromosomes from the father and mother, it becomes a female but turns out being a male if acquires female parent and Y chromosome from the father (“The New York Times”). Females have shown an intriguing characteristic where they inactive X chromosomes in each cell except one. Different scientist and researchers have taken it upon themselves to try and, understand the mechanism of the mysterious X chromosome as well as its inactivation amongst the female. BODY 1. Effects of X-Chromosome i. A team of scientist in the Journal neuron noted a complexity in shutting and waking of chromosomes. Understanding the X- chromosomes mechanism of action, aids in the application of stem cells in treatment procedures (“The New York Times”). ii. Females have more genome diversity than males since different copies of X chromosome. Males have only a single X chromosome hence they do not possess genetic complexity compared to their female counterparts. The copies of X-chromosome possess different genes and this is an advantage since in case of a defective gene, there will be back up from another gene (“The New York Times”). iii. As much as females enjoy a genetic advantage, they face a risk of cancer. In males, absence of the X chromosomes may lead to disorders because of the lack of genetic diversity. 2. Understanding Deactivation of X-Chromosome i. According to a study done by Susumu Ohno, a Japanese biologist who first identified chromosome inactivation, one of the X chromosomes present in females usually becomes dormant and ceases producing proteins (“The New York Times”). ii. Another scientist by name Mary Lyon carried out a research by breeding mice. She realized that some offspring retained hair colour of their mothers and some retained that of their fathers. This explained chromosome inactivation since the colour gene is evident on the X chromosome (“The New York Times”). 3. Experiment to Understand how Females Manage to Deactivate the X- Chromosomes i. Following the discovery by Lyon, Jeremy Nathans from Johns Hopkins University together with his colleagues decided to investigate more on the works of Mary Lyon. They therefore carried out the following experiment. a. TA set of genes was introduced into the mice’ X-chromosome. b. In the presence of an active X chromosome exposed to a chemical trigger, the genes indicated a green fluorescent protein. c. Other mice were engineered in a way that they could show a red protein from an active X chromosomes following exposure to a different chemical. d. These mice were then bred to produce female offspring e. These female offspring genetically obtains a green X emanating from one of the parent and red from the other. f. Chemicals that could trigger them to display colours were introduced into the cells of the mice. g. The cells then displayed a mosaic if red and green colours as they lit up 4. Results from the Experiment i. The scientists realized that one cell might inactivate the mothers X while its adjacent cells shut down the fathers. Two cells could be parallel to each other yet they express a variety of genes. ii. Pictures from this experiment indicate that X chromosome inactivation leads to genetic diversity. Dr. Nathan hopes that his pictures could serve as an atlas in analysing effects of X chromosomes shutting in females (“The New York Times”). iii. The X-chromosomes form both parents could dominate opposite sides of an organ such like mothers X chromosome for the right and fathers X chromosome for the left. Sometimes the X chromosome emanating from either one of the two parents can dominate the entire organ evident in the experiment where they found out that in some mice, the father dominated one eye and the mother the other (“The New York Times”). In addition, some mice indicated that that total X chromosomes coming from the parent underwent deactivation since they did not show any sign of expression. 5. Gene silencing i. The mechanism in which one cells silence its parents’ X-chromosome is not clear to scientists. They however have information on the number of molecules that carry out the silencing procedure, the leaders of these molecules being Xist. This has however raised controversies since contradicting opinions have arisen. Some researchers contend one Xist molecule managed to settle on a definite location the X chromosome and consequently others followed suit hence attaching along its length. Contrary opinions however claim that Xist molecules engulfed the X chromosome at once then attracted other types of molecules to engulf the X- chromosome (“The New York Times”). a. Males possess a single copy of its genes and tend to increase protein production of proteins from X chromosomes. In females, an increase of proteins may lead to an overdose hence they deactivate one of the X chromosomes in order to re balance themselves (“The New York Times”). b. Shutting the Xist in female mice however shows that they had a chance of developing cancer (“The New York Times”). When a cell stops synthesising Xist, the X chromosome that had shut may wake up hence generate extra protein, which can make a cell grow uncontrollably. Conclusion Stem cells can be useful in medical treatments. It is however necessary to understand the mechanism of the X chromosome to avoid using treatments that may lead to consequences. Gabriel Marais of the University of Lyons admitted that the situation was very confusing hence implying that a study that is more thorough is necessary (“The New York Times”). Work Cited “Seeing X Chromosomes in a New Light.” Jan 20, 2014. The New York Times. 20Th January 2014. Web. 24Th July 2014. Read More