Human mitochondrial genetics in the context of Paternal mtDNA transmission in humans

Whole genome sequencing (WGS), also known as full genome sequencing or just genome sequencing, is the process of determining the entirety of the DNA sequence of an organism's genome at a single time. This entails sequencing all of an organism's chromosomal DNA as well as DNA contained in the mitochondria and, for plants, in the chloroplast.

Whole genome sequencing has largely been used as a research tool, but was being introduced to clinics in 2014. In the future of personalized medicine, whole genome sequence data may be an important tool to guide therapeutic intervention. The tool of gene sequencing at SNP level is also used to pinpoint functional variants from association studies and improve the knowledge available to researchers interested in evolutionary biology, and hence may lay the foundation for predicting disease susceptibility and drug response.

The human genome is a complete set of DNA sequences for each of the 22 autosomes and the two distinct sex chromosomes (X and Y). A small DNA molecule is found within individual mitochondria. These are usually treated separately as the nuclear genome and the mitochondrial genome.

Human genomes include both genes and various other types of functional DNA elements. The latter is a diverse category that includes regulatory DNA scaffolding regions, telomeres, centromeres, and origins of replication. In addition, there are large numbers of transposable elements, inserted viral DNA, non-functional pseudogenes and simple, highly repetitive sequences. Introns make up a large percentage of the human genome.

In genetics, a chromosomal rearrangement is a mutation that is a type of chromosome abnormality involving a change in the structure of the native chromosome. Such changes may involve several different classes of events, like deletions, duplications, inversions, and translocations. Usually, these events are caused by a breakage in the DNA double helices at two different locations, followed by a rejoining of the broken ends to produce a new chromosomal arrangement of genes, different from the gene order of the chromosomes before they were broken. Structural chromosomal abnormalities are estimated to occur in around 0.5% of newborn infants.

Some chromosomal regions are more prone to rearrangement than others and thus are the source of genetic diseases and cancer. This instability is usually due to the propensity of these regions to misalign during DNA repair, exacerbated by defects of the appearance of replication proteins (like FEN1 or Pol δ) that ubiquitously affect the integrity of the genome.Complex chromosomal rearrangements (CCR) are rarely seen in the general population and are defined as structural chromosomal rearrangements with at least three breakpoints with exchange of genetic material between two or more chromosomes. Some forms of campomelic dysplasia, for example, result from CCRs.

G-banding, G banding or Giemsa banding is a technique used in cytogenetics to produce a visible karyotype by staining condensed chromosomes. It is the most common chromosome banding method. It is useful for identifying genetic diseases (mainly chromosomal abnormalities) through the photographic representation of the entire chromosome complement.