Structural variation in the human genome information
Genomic alterations, varying between individuals
Structural Variation
Structural variation in the human genome is operationally defined as genomic alterations, varying between individuals, that involve DNA segments larger than 1 kilo base (kb), and could be either microscopic or submicroscopic.[1] This definition distinguishes them from smaller variants that are less than 1 kb in size such as short deletions, insertions, and single nucleotide variants.
Humans have an incredibly complex and intricate genome that has been shaped and modified over time by evolution. About 99.9% of the DNA-sequence in the human genome is conserved between individuals from all over the world, but some variation does exist.[1] Single nucleotide polymorphisms (SNPs) are considered to be the largest contributor to genetic variation in humans since they are so abundant and easily detectable.[2] It is estimated that there are at least 10 million SNPs within the human population but there are also many other types of genetic variants and they occur at dramatically different scales.[1] The variation between genomes in the human population range from single nucleotide polymorphisms to dramatic alterations in the human karyotype.[3]
Human genetic variation is responsible for the phenotypic differences between individuals in the human population. There are different types of genetic variation and it is studied extensively in order to better understand its significance. These studies lead to discoveries associating genetic variants to certain phenotypes as well as their implications in disease. At first, before DNA sequencing technologies, variation was studied and observed exclusively at a microscopic scale. At this scale, the only observations made were differences in chromosome number and chromosome structure. These variants that are about 3 Mb or larger in size are considered microscopic structural variants.[1] This scale is large enough to be visualized using a microscope and include aneuploidies, heteromorphisms, and chromosomal rearrangements.[1] When DNA sequencing was introduced, it opened the door to finding smaller and incredibly more sequence variations including SNPs and minisatellites. This also includes small inversions, duplications, insertions, and deletions that are under 1 kb in size.[1]
In the human genome project the human genome was successfully sequenced, which provided a reference human genome for comparison of genetic variation. With improving sequencing technologies and the reference genome, more and more variations were found of several different sizes that were larger than 1 kb but smaller than microscopic variants. These variants ranging from about 1 Kb to 3 Mb in size are considered submicroscopic structural variants.[1] These recently discovered structural variants are thought to play a very significant role in phenotypic diversity and disease susceptibility.
^ abcdefgFeuk, L.; Carson, A.R.; Schere, S.W. (2006). "Structural variation in the human genome". Nature Reviews Genetics. 7 (2): 85–97. doi:10.1038/nrg1767. PMID 16418744. S2CID 17255998.
^Nguyen, D.Q.; Webber, C.; Ponting, C.P. (2006). "Bias of selection on human copy-number variants". PLOS Genetics. 2 (2): e20. CiteSeerX 10.1.1.276.7715. doi:10.1371/journal.pgen.0020020. PMC 1366494. PMID 16482228.
genome browsers and bioinformatic databases have a list of structuralvariationsinhumangenome with an emphasis on CNVs, and can show them inthe genome...
Thehumangenome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA...
frequently in certain geographic regions or in people with ancestry from those regions, this variation accounts for a small portion (~15%) of humangenome variability...
Copy number variation (CNV) is a phenomenon in which sections of thegenome are repeated and the number of repeats inthegenome varies between individuals...
Andrew R. Carson & Stephen W. Scherer (February 2006). "Structuralvariationinthehumangenome". Nature Reviews Genetics. 7 (2): 85–97. doi:10.1038/nrg1767...
establish the most detailed catalogue of human genetic variation at the time. Scientists planned to sequence thegenomes of at least one thousand anonymous...
TheHumanGenome Project (HGP) was an international scientific research project with the goal of determining the base pairs that make up human DNA, and...
found inhuman DNA that were not fully uncovered by the original HumanGenome Project study, scientists reported the first end-to-end humangenome sequence...
of human variability, health and disease, including research on the genetics of autism spectrum disorder and structuralvariation of thehumangenome. The...
mutation of their genomes than human or bacterial cells. In general viruses with shorter genomes have faster rates of mutation than longer genomes since they...
RE, et al. (November 2012). "An integrated map of genetic variation from 1,092 humangenomes". Nature. 491 (7422): 56–65. Bibcode:2012Natur.491...56T....
Ma, Hanzhou (August 2011). "Structuralvariationin two humangenomes mapped at single-nucleotide resolution by whole genome de novo assembly". Nature Biotechnology...
Human variability, or humanvariation, is the range of possible values for any characteristic, physical or mental, of human beings. Frequently debated...
percent of humans are intersex, sometimes due to variationsin sex chromosomes. Thehuman mitochondrial genome (shown at bottom left inthe schematic karyogram...
Thegenome and proteins of HIV (human immunodeficiency virus) have been the subject of extensive research since the discovery of the virus in 1983. "In...
TheHumanGenome Diversity Project (HGDP) was started by Stanford University's Morrison Institute in 1990s along with collaboration of scientists around...
46 per cell. In addition to these, human cells have many hundreds of copies of the mitochondrial genome. Sequencing of thehumangenome has provided a...
Human somatic variations are somatic mutations (mutations that occur in somatic cells) both at early stages of development and in adult cells. These variations...
2014. The standard is currently in version 4.3, although the 1000 Genomes Project has developed its own specification for structuralvariations such as...
(2005). Segmental Duplications and Copy-Number VariationintheHumanGenome. American Journal of Human Genetics, 77(1), 78–88. Bailey, Jeffrey A. et al...
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