A chromosome is a single strand of DNA which has been condensed and super coiled inside a cell which carries genetic information. Chromosome consists of a centromere located at the Centre of the chromosome, a short arm and a long arm, with different genes on the chromosome called locus specific sites. Each chromosome varies from 0.2 to 20 micrometers in length and can contain up to 10,000,000,000 nucleotides.
The x chromosome is one of the 23 pairs of human chromosomes and is the largest of the two sex chromosomes, the other being the chromosome Y. The x chromosome is unique in what it represents about 5percent of total DNA from cells. It contains 155 million pairs of nucleotides and have between 900 and 1,400 genes which are essential for the different processes of development and life.
The genome of the women are exceptional in that they have two of the same chromosome. However, the two x are not coded or block at the same time to reduce the redundancy of expressed genes. Therefore, one of the x chromosomes is inhibited by a process called X-Inactivation. Packaging of the x chromosome inactivated in a highly condensed DNA called heterochromatin molecule inhibits the expression of several copies of the same gene at the same time. This process is to ensure that women have twice as many genes on chromosome of x being expressed in men. This can be very useful regulated in women. The benefits are very obvious when it comes to the immune system. When a woman x chromosome is defective or compromised, the other x chromosome can express themselves and to support the necessary functions.
There are many disorders associated with the X chromosome. Mutations in the chromosome number often unnoticed. A woman who has one x chromosome and a second is missing or altered physically is known for having the Turner Syndrome. A woman who has the Turner Syndrome normally pieces of small size and has the hair growth more than a woman with normal two X chromosomes. It is also not fertile that it cannot bear children. A woman who has three x is characterized as having the Triple X Syndrome. Women with a Triple X Syndrome may display behavioural difficulties, high stature, muscular tone reduced and in rare cases, infertility. A woman who has four or more x appears physically normal, but is almost always mentally delayed.
The x chromosome is one of the most mysterious and unique chromosomes. Scientists do not yet have all the answers on how these genes are settled between the two x researchers know that it has something to do with the MICRORNA that are essential in the control of the expression of the genes, but the triggers in the body resulting in the MICRORNA to bind and inhibit genes are unknown. This process is called Epigenetics and is still a whole new field in science. Genetics helps us to understand the theory behind this process occur between genes and chromosomes and how that affects the population change.
Juliane Mr. Liberto
Cycle of the University of California Merced
Bio 140-genetics
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