Structural Variation

Structural variation (SV) generally refers to the change of DNA base fragment (>50 bp) in the human genome. It could alter thousands of DNA nucleotides and thus significantly influence disease and phenotype.

Copy number variation (CNV) is caused by the rearrangement of the genome. It generally refers to the increase or decrease in the copy number of large fragments of the genome with a length of 1KB or more, mainly manifested as deletions and duplications at the submicroscopic level. It is an important part of the structural variation (SV) of the genome.

InDel(Insertion and Deletion) refers to the insertion or deletion sequence of small fragments in the genome, and its length is between 1-50bp. The reason is that the read size of Illumina sequencing is about 100bp, including single-end sequencing (single-end, 100bp) and paired-end sequencing (paired-end, 2 x 100bp). Small InDel variation is generally less than SNP variation, which also reflects the difference between the sample and the reference genome. InDel in the coding region will cause frameshift mutations, leading to changes in gene function.

Copy Number Polymorphism(CNP) refers to the genetic trait involving the number of copies of a particular gene present in the genome of an individual.

Short Tandem Repeat : A short sequence of DNA, usually 1 to 4 basepairs (a unit of DNA), that is repeated together in a row along the DNA molecule. There is variation from person to person in the number of repeats. There are hundreds of places in human DNA that contain microsatellites.

Any type of genetic recombination involving exchange of DNA between non-homologous chromosomes, which often occurs as the result of non-homologous end-joining of broken DNA strands. Chromosomal translocation is involved in repairing broken DNA and in maintaining cell viability at the expense of long term genomic stability. This process is is associated with particular types of leukemia, infertility and Down Syndrome.