Mean Genes Pdf EXCLUSIVE Free 15
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Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. Chromosome 15 likely contains 600 to 700 genes that provide instructions for making proteins. These proteins perform a variety of different roles in the body.
Dup15q syndrome is caused by the presence of at least one extra copy of a region of chromosome 15 called 15q11.2-q13.1. This region is also called the Prader-Willi/Angelman critical region (PWACR) because genetic changes in it are also involved in conditions called Prader-Willi syndrome and Angelman syndrome (described below). Dup15q syndrome arises only if the chromosome abnormality occurs on the copy of the chromosome inherited from the mother (the maternal copy). People normally inherit one copy of chromosome 15 from each parent. However, some genes on this chromosome, including some of those in the 15q11.2-q13.1 region, are turned on (active) only on the maternal copy. This parent-specific gene activation results from a phenomenon called genomic imprinting.
In all cases of dup15q syndrome, the duplicated genetic material results in extra copies of certain genes involved in development. This extra genetic material disrupts normal development, causing the characteristic features of this disorder. People with dup15q syndrome resulting from an interstitial duplication often have milder signs and symptoms than those in whom the disorder results from an isodicentric chromosome 15.
15q13.3 microdeletion is a chromosomal change in which a small piece of chromosome 15 is deleted in each cell. The deletion occurs on the q arm of the chromosome at a position designated q13.3. Most people with a 15q13.3 microdeletion are missing a sequence of about 2 million DNA base pairs, also written as 2 megabases (Mb). The exact size of the deleted region varies, but it typically contains at least six genes. It is unclear how a loss of these genes increases the risk of intellectual disability, seizures, behavioral problems, and psychiatric disorders in some individuals with a 15q13.3 microdeletion.
15q24 microdeletion is a chromosomal change in which a small piece of chromosome 15 is deleted in each cell. Specifically, affected individuals are missing between 1.7 Mb and 6.1 Mb of DNA at position q24 on chromosome 15. The exact size of the deletion varies, but all individuals are missing the same 1.2 Mb region. This region contains several genes that are thought to be important for normal development. It is unclear how a loss of these genes leads to intellectual disability, distinctive facial features, and other abnormalities often seen in people with a 15q24 microdeletion.
The PML-RARα protein functions differently than the protein products from the normal PML and RARA genes. The PML gene on chromosome 15 provides instructions for a protein that acts as a tumor suppressor, which means it prevents cells from growing and dividing too rapidly or in an uncontrolled way. The PML protein blocks cell growth and division (proliferation) and induces self-destruction (apoptosis) in combination with other proteins. The RARA gene on chromosome 17 provides instructions for making a transcription factor called the retinoic acid receptor alpha (RARα). A transcription factor is a protein that attaches (binds) to specific regions of DNA and helps control the activity of particular genes. Normally, the RARα protein controls the activity (transcription) of genes important for the maturation (differentiation) of immature white blood cells beyond a particular stage called the promyelocyte. The PML-RARα protein interferes with the normal function of both the PML and the RARα proteins. As a result, blood cells are stuck at the promyelocyte stage, and they proliferate abnormally. Excess promyelocytes accumulate in the bone marrow and normal white blood cells cannot form, leading to acute promyelocytic leukemia.
About 10 percent of cases of Angelman syndrome are caused by a variant in the UBE3A gene, and another 3 percent results from a defect in the DNA region that controls the activation of the UBE3A gene and other genes on the maternal copy of chromosome 15. In a small percentage of cases, Angelman syndrome is caused by a chromosomal rearrangement (translocation) or by a variant in a gene other than UBE3A. These genetic changes abnormally inactivate the UBE3A gene.
Prader-Willi syndrome is caused by a loss of active genes in a region of chromosome 15. This region is located on the q arm of the chromosome and is designated 15q11-q13. It is the same part of chromosome 15 that is usually affected in people with Angelman syndrome, although different genes are associated with the two disorders. People can have either Prader-Willi syndrome or Angelman syndrome, but they typically cannot have both.
People normally inherit one copy of chromosome 15 from each parent. Some genes on this chromosome are turned on (active) only on the copy inherited from a person's father (the paternal copy). This parent-specific gene activation results from a phenomenon called genomic imprinting.
In about 70 percent of cases, Prader-Willi syndrome occurs when the 15q11-q13 region of the paternal chromosome 15 is deleted in each cell. A person with this chromosomal change will be missing certain critical genes in this region because the genes on the paternal copy have been deleted, and the genes on the maternal copy are turned off (inactive). Researchers are working to identify which missing genes are associated with the characteristic features of Prader-Willi syndrome.
In about 25 percent of cases, people with Prader-Willi syndrome inherit two copies of chromosome 15 from their mother instead of one copy from each parent. This phenomenon is called maternal UPD. A person with two maternal copies of chromosome 15 will have no active copies of certain genes in the 15q11-q13 region.
In a small percentage of cases, Prader-Willi syndrome is caused by a chromosomal rearrangement called a translocation. Rarely, the condition results from a variant or other change that abnormally inactivates genes on the paternal copy of chromosome 15.
Sensorineural deafness and male infertility is caused by a deletion of genetic material on the q arm of chromosome 15. The symptoms of sensorineural deafness and male infertility are related to the loss of multiple genes in this region. The size of the deletion varies among affected individuals. Researchers have determined that the loss of a particular gene on chromosome 15, STRC, is responsible for hearing loss in affected individuals. The loss of another gene, CATSPER2, in the same region of chromosome 15 is responsible for sperm abnormalities, which lead to an inability to father children (infertility) in affected males. Researchers are working to determine how the loss of additional genes in the deleted region affects people with sensorineural deafness and male infertility.
People with ASD may face a wide range of issues, which means that there is no single best treatment for ASD. Working closely with a health care provider is an important part of finding the right combination of treatment and services.
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Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species boundaries to produce improved or novel organisms. New DNA is obtained by either isolating and copying the genetic material of interest using recombinant DNA methods or by artificially synthesising the DNA. A construct is usually created and used to insert this DNA into the host organism. The first recombinant DNA molecule was made by Paul Berg in 1972 by combining DNA from the monkey virus SV40 with the lambda virus. As well as inserting genes, the process can be used to remove, or "knock out", genes. The new DNA can be inserted randomly, or targeted to a specific part of the genome.[1]
Genetic engineering has been applied in numerous fields including research, medicine, industrial biotechnology and agriculture. In research, GMOs are used to study gene function and expression through loss of function, gain of function, tracking and expression experiments. By knocking out genes responsible for certain conditions it is possible to create animal model organisms of human diseases. As well as producing hormones, vaccines and other drugs, genetic engineering has the potential to cure genetic diseases through gene therapy. The same techniques that are used to produce drugs can also have industrial applications such as producing enzymes for laundry detergent, cheeses and other products.
Genetic engineering is a process that alters the genetic structure of an organism by either removing or introducing DNA, or modifying existing genetic material in situ. Unlike traditional animal and plant breeding, which involves doing multiple crosses and then selecting for the organism with the desired phenotype, genetic engineering takes the gene directly from one organism and delivers it to the other. This is much faster, can be used to insert any genes from any organism (even ones from different domains) and prevents other undesirable genes from also being added.[4]
Genetic engineering could potentially fix severe genetic disorders in humans by replacing the defective gene with a functioning one.[5] It is an important tool in research that allows the function of specific genes to be studied.[6] Drugs, vaccines and other products have been harvested from organisms engineered to produce them.[7] Crops have been developed that aid food security by increasing yield, nutritional value and tolerance to environmental stresses.[8] 2b1af7f3a8