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STR Analysis
Short tandem repeat (STR) analysis is a common molecular biology method used to compare allele repeats at specific loci in DNA between two or more samples. A short tandem repeat is a microsatellite with repeat units that are 2 to 7 base pairs in length, with the number of repeats varying among individuals, making STRs effective for human identification purposes. This method differs from restriction fragment length polymorphism analysis (RFLP) since STR analysis does not cut the DNA with restriction enzymes. Instead, polymerase chain reaction (PCR) is employed to discover the lengths of the short tandem repeats based on the length of the PCR product. Forensic uses STR analysis is a tool in forensic analysis that evaluates specific STR regions found on nuclear DNA. The variable (polymorphic) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another. Scientific tools such as FBI approved STRmix incorporat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Short Tandem Repeat (STR) Analysis
A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. They have a higher mutation rate than other areas of DNA leading to high genetic diversity. Microsatellites are often referred to as short tandem repeats (STRs) by forensic geneticists and in genetic genealogy, or as simple sequence repeats (SSRs) by plant geneticists. Microsatellites and their longer cousins, the minisatellites, together are classified as VNTR (variable number of tandem repeats) DNA. The name "satellite" DNA refers to the early observation that centrifugation of genomic DNA in a test tube separates a prominent layer of bulk DNA from accompanying "satellite" layers of repetitive DNA. They are widely used for DNA profiling in cancer diagnosis, in kinship analysis (especially paternity testing) and in forensic identific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-nucleotide Polymorphism
In genetics and bioinformatics, a single-nucleotide polymorphism (SNP ; plural SNPs ) is a germline substitution of a single nucleotide at a specific position in the genome. Although certain definitions require the substitution to be present in a sufficiently large fraction of the population (e.g. 1% or more), many publications do not apply such a frequency threshold. For example, a Guanine, G nucleotide present at a specific location in a reference genome may be replaced by an Adenine, A in a minority of individuals. The two possible nucleotide variations of this SNP – G or A – are called alleles. SNPs can help explain differences in susceptibility to a wide range of diseases across a population. For example, a common SNP in the Factor H, CFH gene is associated with increased risk of age-related macular degeneration. Differences in the severity of an illness or response to treatments may also be manifestations of genetic variations caused by SNPs. For example, two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biochemistry Detection Methods
Biochemistry, or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, and metabolism. Over the last decades of the 20th century, biochemistry has become successful at explaining living processes through these three disciplines. Almost all areas of the life sciences are being uncovered and developed through biochemical methodology and research. Voet (2005), p. 3. Biochemistry focuses on understanding the chemical basis that allows biological molecules to give rise to the processes that occur within living cells and between cells, Karp (2009), p. 2. in turn relating greatly to the understanding of tissues and organs as well as organism structure and function. Miller (2012). p. 62. Biochemistry is closely related to molecular biology, the study of the molecular mechanisms of biological phenomena.Astbury ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth Human STR Allele Frequencies Database
The Earth Human STR Allele Frequencies Database is a scientific project based on a dynamic web interface and a relational database management system. Its main purpose is the management of STR populational data reported from all over the world, providing highly specialized population genetics tools and also an overview of world population genetic structure at global scale. At the bottom of EHSTRAFD approach stays peer-review journals standardization trend in publishing populational data and most important, the allele frequencies gradient distribution over vast geographical areas.Roewer L, Croucher PJ, Willuweit S, Lu TT, Kayser M, Lessig R, de Knijff P, Jobling MA, Tyler-Smith C, Krawczak M. Signature of recent historical events in the European Y-chromosomal STR haplotype distribution. Hum Genet. 2005;116(4):279-91 Database Tools (Modules) ''Allele Frequency Global Tracking'' (AFGT) - allows searching for allele frequency distribution at global and regional level. STR Loci are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of X-STR Markers
The following X-STR markers are used in genealogical DNA testing and other forms of relationship testing. {, class="wikitable" !STR # !notes !DNA sequence repeat motif !alleles !mutation rate !links , - !DXS10011 , , , , , , - !DXS10066 , DXS10066 is also known as Penta X-16. , , , , , - !DXS10067 , DXS10067 is also known as Penta X-12. , , , , , - !DXS10068 , DXS10068 is also known as Penta X-13. , , , , , - !DXS10069 , DXS10069 is also known as Penta X-15. , , , , , - !DXS10074 , , , , , , - !DXS10075 , , , , , , - !DXS10079 , , , , , , - !DXS10129 , DXS10129 is also known as Penta X-10. , , , , , - !DXS10130 , DXS10130 is also known as Penta X-3. , , , , , - !DXS10131 , , , , , , - !DXS10132 , DXS10132 is also known as Penta X-17. , , , , , - !DXS10133 , DXS10133 is also known as Penta X-18. , , , , , - !DXS6807 , , , , , , - !DXS7132 , , , , , , - !DXS7423 , , , , , , - !DXS8377 , , , , , , - !DXS98 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Y-STR Markers
The Y-STR markers in the following list are commonly used in forensic and genealogical DNA testing. DYS454 is the least diverse, and multi-copy marker DYS464 is the most diverse Y-STR marker. The location on the Y-chromosome of numbered Y-STR markers can be roughly given with cytogenetic localization. For example, DYS449 is located at Yp11.2 - meaning the Y-chromosome, petit arm, band 1, sub-band 1, sub-sub-band 2 - DYS449. Forensic labs usually use PowerPlex Y (Promega Corporation) and Yfiler (Applied Biosystems) kits that examine 12 or 17 Y-STRs, respectively. Genealogical DNA test labs examine up to 700 Y-STRs. Mutation rates Mutation rates are those per generation, as estimated in Chandler (2006). The quoted estimated errors are typically +/- 15-20%. Alternative estimates (for forensic use therefore not all markers are covered) from observed pedigrees are also available at the Y Chromosome Haplotype Reference Database. It appears that some trinucleotide markers may have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Y-STR
A Y-STR is a short tandem repeat (STR) on the Y-chromosome. Y-STRs are often used in forensics, paternity, and genealogical DNA testing. Y-STRs are taken specifically from the male Y chromosome. These Y-STRs provide a weaker analysis than autosomal STRs because the Y chromosome is only found in males, which are only passed down by the father, making the Y chromosome in any paternal line practically identical. This causes a significantly smaller amount of distinction between Y-STR samples. Autosomal STRs provide a much stronger analytical power because of the random matching that occurs between pairs of chromosomes during the zygote-making process. "STR Analysis" Nomenclature Y-STRs are assigned names by the[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snpstr
A SNPSTR is a compound genetic marker composed of one or more SNPs and one microsatellite (STR). Autosomal SNPSTRs, which contain an SNP and a microsatellite within 500 base pairs of one another, were discovered in 2002. More recently a database that contains all SNPSTRs in five model genomes, including human, has been created.AGRAFIOTI I AND STUMPF MPH (2007) "SNPSTR: a database of compound microsatellite-SNP markers" Nucleic Acids Research 35(Database issue): 71–75. Usage and importance There has been widespread and growing interest in genetic markers suitable for drawing population genetic inferences about past demographic events and to detect the effects of selection. Single nucleotide polymorphisms ( SNPs) and microsatellites (or short tandem repeats, STRs) have received great attention in the analysis of human population history, even though they have both disadvantages. It was thus suggested that the combination of these two markers could give rise to better conclusions. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
STR Multiplex System
An STR multiplex system is used to identify specific short tandem repeats (STRs). STR polymorphisms are genetic markers that may be used to identify a DNA sequence. The FBI analyses 13 specific STR loci for their database. These may be used in many areas of genetics in addition to their forensic uses. One can think of a STR multiplex system as a collection of specific STRs which are positionally conserved on a target genome. Hence these can be used as markers. A number of different STRs along with their loci in a particular genome can be used for genotyping. For example, the STR multiplex system AmpFlSTR Profiler Plus which analyses nine different STRs (3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820) plus Amelogenin Amelogenins are a group of protein isoforms produced by alternative splicing or proteolysis from the '' AMELX'' gene, on the X chromosome, and also the '' AMELY'' gene in males, on the Y chromosome. They are involved in amelogenesis, the dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monozygotic Twins
Twins are two offspring produced by the same pregnancy.MedicineNet > Definition of Twin Last Editorial Review: 19 June 2000 Twins can be either ''monozygotic'' ('identical'), meaning that they develop from one zygote, which splits and forms two embryos, or ''dizygotic'' ('non-identical' or 'fraternal'), meaning that each twin develops from a separate egg and each egg is fertilized by its own sperm cell. Since identical twins develop from one zygote, they will share the same sex, while fraternal twins may or may not. In very rare cases, fraternal or (semi-) identical twins can have the same mother and different fathers ( heteropaternal superfecundation). In contrast, a fetus that develops alone in the womb (the much more common case in humans) is called a ''singleton'', and the general term for one offspring of a multiple birth is a ''multiple''. Unrelated look-alikes whose resemblance parallels that of twins are referred to as doppelgänger. Statistics The human twin birth rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bayes' Theorem
Bayes' theorem (alternatively Bayes' law or Bayes' rule, after Thomas Bayes) gives a mathematical rule for inverting Conditional probability, conditional probabilities, allowing one to find the probability of a cause given its effect. For example, if the risk of developing health problems is known to increase with age, Bayes' theorem allows the risk to someone of a known age to be assessed more accurately by conditioning it relative to their age, rather than assuming that the person is typical of the population as a whole. Based on Bayes' law, both the prevalence of a disease in a given population and the error rate of an infectious disease test must be taken into account to evaluate the meaning of a positive test result and avoid the ''base-rate fallacy''. One of Bayes' theorem's many applications is Bayesian inference, an approach to statistical inference, where it is used to invert the probability of Realization (probability), observations given a model configuration (i.e., th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Independent Assortment
Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularized by William Bateson. These principles were initially controversial. When Mendel's theories were integrated with the Boveri–Sutton chromosome theory of inheritance by Thomas Hunt Morgan in 1915, they became the core of classical genetics. Ronald Fisher combined these ideas with the theory of natural selection in his 1930 book ''The Genetical Theory of Natural Selection'', putting evolution onto a mathematical footing and forming the basis for population genetics within the modern evolutionary synthesis. History The principles of Mendelian inheritance were named for and first derived by Gregor Johann Mendel, a nineteenth-century Moravian monk who formulated his ideas after conducting simple hybridization experiments with pea plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
