When every child is born they are born with two sets of chromosomes. 23 chromosomes are from the mother and 23 chromosomes from the father, creating a total of 46 chromosomes for the child. But for some children born today, they are born with chromosome abnormalities. Chromosome abnormalities involve sex chromosomes and are gender specific (O’Neil). With today’s technology and past studies, we are able to determine chromosome abnormalities and the syndromes that are formed by these abnormalities. Chromosome abnormalities happen when there is something wrong in the cell division, two kinds of cell division is mitosis and meiosis. Mitosis is the process where two daughter cells each having the same number and kind of chromosomes as the parent nucleus split into identical cells, they undergo this change through four phases. These phases are called Prophase, Metaphase, Anaphase, and Telophase. Meiosis is where the daughter cell has one half the numbers of chromosomes as the parent cells and involves the divisions of two cells and therefore produces four daughter cells. Meiosis undergoes the same phases as Mitosis but undergoes two times. “In both processes, the correct number of chromosomes is supposed to end up in the resulting cells. However, errors in cell division can result in cells with too few or too many copies of a chromosome. Errors can also occur when the chromosomes are being duplicated” (Genome). With chromosome abnormalities, there are many different types that can be categorized into two basic groups. The first group is numerical abnormalities which happen “when an individual is missing either a chromosome from a pair (monosomy) or has more than two chromosomes of a pair (trisomy)” (Genome). The second group is called structural abnormalities. “Structural abnormalities occur when the chromosomal morphology is altered due to an unusual location
Mitosis describes the reproduction of somatic cells, and Meiosis describes the reproduction of sex cells. We have discussed that Interphase, although not actually a part of Mitosis, is the longest phase and that Prophase involves the dissolution of the nuclear envelope, the condensing of chromatin into chromosomes, and the formation of mitotic spindles that attach to the centromeres of the chromosome pairs. After Prophase comes Metaphase where the chromosomes line up in the center of the cell at the metaphase plate. Next, Anaphase occurs where sister chromatids separate to become two separate chromosomes that then move to opposite poles of the cell. This results in the cell’s shape becoming elongated and the chromosome pairs splitting apart. Lastly, Telophase follows Anaphase and nuclei form around the two sets of chromosomes that then become less condensed. In Telophase, the microtubules break down too, and this phase is overlapped at the end of Mitosis with Cytokinesis that involves the final splitting of the two
Turner’s syndrome is a genetic conditions that affects the female’s sex chromosome. In (http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001417/) Turner’s syndrome occurs when cells are missing all or part of an X chromosome. It’s common of the female patient to only have one X chromosome. Although, some individuals may have two X chromosomes but one is defective. It is thought that an estimated 1 out of 2000-2500 females suffer from this genetic condition worldwide but it’s usually females with this condition don’t survive their birth. Due to this abnormality, the genes that is defective “affect the growth and sexual development of the female” (http://learn.genetics.utah.edu/content/disorders/whataregd/turner/). However other disabilities and delays do occur even though these traits can vary case by case.
Every cell contains forty-six chromosomes (twenty-three pairs). One, out of the twenty-three pairs, is in control of a person’s gender. There two different kinds of chromosomes: X and Y. Males are born with one X chromosome and one Y chromosome. Females, however, are born with two X chromosomes. According to Cindy Dunham and Catherine H. Ward, girls with Turner syndrome are missing part of, or all of the X chromosome (3). The chromosome becomes absent before or shortly after conception (Overview par. 3). Girls diagnosed with Turner syndrome are confirme...
. Other mistakes that can occur during meiosis include translocation, within which a part of one chromosome becomes connected to another, and deletion, in which part of one chromosome is lost entirely. The severity of the results of those disorders depends entirely on the dimensions of the chromosome fragment concerned and, therefore, the genetic data contained in it. Modern technology will find these genetic abnormalities early within the development of the foetus, however at the moment, very little will be done to correct or perhaps treat the diseases ensuing from
Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 21. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 21 in each of the body's cells.
Genomic instability can be manifested as an abnormality from multiple chromosomal alterations. Genomic instability can also occur from errors in DNA replication or better known as microsatellite instability (MSI).
The most commonly found, and commonly known type of Trisomy eighteen which occurring in about ninety-five percent of all cases reported is the type known as full trisomy. During the formation of the full trisomy type of trisomy eighteen the extra chromosome occurs in every single cell in the baby’s body. This type of trisomy eighteen is not hereditary however, which means this type is not found as family trait, it is a random type. The next type of trisomy eighteen is known as partial or translocation, which happens to occurs in only about three percent of patients with trisomy eighteen. Partial trisomy eighteen occurs when people have two copies of chromosome eighteen instead of one, and a piece of extra genetic material from the chromosome eighteen. Partial Trisomy eighteen syndrome may be caused by hereditary factors. The final type of trisomy eighteen is known as the Mosaic Trisomy eighteen. Mosaic Trisomy is very rare type of trisomy ei, found in about two percent of all trisomy eighteen cases. Mosaic Trisomy eighteen is when an extra copy of the eighteenth chromosome is found in some, but not all of the cells in the person’s body. Mosaic trisomy eighteen is however not hereditary. No matter the type of trisomy eighteen a person is diagnosed whether it is full, partial, or mosaic, it is important that people understand that trisomy eighteen was not caused by anything done or not done by
Each chromosome carries a unique genetic code that will express itself as a particular gene. An embryo receives two sets of 23 chromosomes from the mother and father through fertilization. Every gene they inherit from the mother, they also inherit from the father. Out of both sets of 23, the embryo receives a sex chromosome, which determines its gender. The mother always gives an X to the embryo, where as the father can either give another X to create a girl or a Y to create a boy. The chromosome sets pair up, and then separate when the cell divides. One then receives different combinations of half the mother and father’s genes in their cells during development. Through these combinations, one may inherit certain genes from either the mother or father through gene dominance. They are also able to inherit genetic conditions by autosomal dominance, autosomal recessive, or sex-linked inheritance. Lastly, a child may receive a mutated or extra chromosome that codes for a genetic defect or condition. The parents would not be able to find out any of these things until after birth, which in some cases is too late to save the
In 1942 Doctor Harry Klinefelter wrote a paper about some men who he found had strange symptoms. These symptoms included very little facial/body hair, small testes, and an inability to produce sperm. Seventeen years later in 1959 the extra X chromosome that is characteristic of the condition was discovered. Klinefelter Syndrome is a condition that affects male chromosomes. Humans in general have about 46 chromosomes in total. Out of these 46, only two will determine if a person will be male or female. The sex chromosomes in women typically present as XX, while the sex chromosomes in males present as XY. With Klinefelter syndrome, also known as (47, XXY) and XXY Syndrome only males are able to affected with this chromosomal condition where they end up with an extra X chromosome on almost all of their cells.
This is usually caused by non-disjunction. Other causes of TS cells are missing all or part of an X chromosome. Another words instead of XX or XY, it’s an XO chromosome. The missing X, or Y, Chromosome of TS causes errors during fetal development and other problems after birth.
Meiosis is the process of dividing in order to create new cells. This process occurs in germ and sex cells. Meiosis ends with 4 daughter cells and the chromosome number is cut in half, while in mitosis, there are 2 identical cells in the end. Meiosis and Mitosis go through the same process, but meiosis goes through it twice.
Sometimes when you look at two children from one family, and they look so different, you think one of them must be adopted. However, this is not necessarily the case. It is possible for parents to have children that look completely different from their parents. Each parent has 46 chromosomes divided into pairs of two. The pairs are one from the maternal side and one from the paternal side. Each parent passes on 23 chromosomes, one from each pair. This is randomly selected which chromosome gets passed on. Alleles are a variant of the gene within the chromosomes. With various combinations of alleles, there are over 8 million different human possibilities to occur from one couple. This is why two parents can have children that are all different.
Meiosis is a special type of cell division that occurs during formation of sperm and egg cells and gives them the correct number of chromosomes. Since a sperm and egg unite during fertilization, each must have only half the number of chromosomes other body cells have. Otherwise, the fertilized cell would have too many.
A genetic mutation is a permanent change in the sequence of the DNA that makes up a gene. A mutation of these sorts can be caused by either inheritance from the parent or caused sometime during the life of someone. The mutation that has been inherited is called a germline mutation. Germline mutations affect virtually the entire body, and they seem to be present in every cell. A somatic mutation, or one that is caused in the DNA of a single cell sometime during the life, can be caused by an environmental factor or a wrong bonding in the DNA molecule. These cannot be passed down to the next generation of children because they occur in a specific cell as opposed to in a reproductive cell. Some mutations occur in the embryo as it is growing. These may occur during cell division, and some of the cells may or may not inherit this mutation. Some mutations are extremely rare, and others are incredibly common. Those that occur in more than one percent across a population are considered polymorphisms. Polymorphisms are considered normal variations in DNA, and they are known to cause simple changes such as variations in blood types and hair color. Although these are not typically fatal, they can influence the creation of some disorders (Lister Hill National Center for Biomedical Communications, U.S. National Library of Medicine, National Institutes of Health, Department of Health and Human Services, USA.gov, 2013).
...omosomes or genetic/chromosomal disorders. The most common type of genetic or chromosomal disorder is Down Syndrome or trisomy 21 (Cherry, n.d.). The condition occurs when a child has three chromosomes at the site of the twenty-first chromosome rather than the normal two. Some of the most common signs of Down Syndrome include round face, thick tongue, slanted eyes, hearing problems, heart defects, and intellectual impairment.