Haplogroup

A haplotype is a group of alleles in an organism that are inherited together from a single parent, and a haplogroup (haploid from the ἁπλοῦς, haploûs, "onefold, simple" and group) is a group of similar haplotypes that share a common ancestor with a single-nucleotide polymorphism mutation. More specifically, a haplotype is a combination of alleles at different chromosomal regions that are closely linked and that tend to be inherited together. As a haplogroup consists of similar haplotypes, it is usually possible to predict a haplogroup from haplotypes. Haplogroups pertain to a single line of descent. As such, membership of a haplogroup, by any individual, relies on a relatively small proportion of the genetic material possessed by that individual. Each haplogroup originates from, and remains part of, a preceding single haplogroup (or paragroup). As such, any related group of haplogroups may be precisely modelled as a nested hierarchy, in which each set (haplogroup) is also a subset of a single broader set (as opposed, that is, to biparental models, such as human family trees). Haplogroups are normally identified by an initial letter of the alphabet, and refinements consist of additional number and letter combinations, such as (for example) A → A1 → A1a. In human genetics, the haplogroups most commonly studied are Y-chromosome (Y-DNA) haplogroups and mitochondrial DNA (mtDNA) haplogroups, each of which can be used to define genetic populations. Y-DNA is passed solely along the patrilineal line, from father to son, while mtDNA is passed down the matrilineal line, from mother to offspring of both sexes. Neither recombines, and thus Y-DNA and mtDNA change only by chance mutation at each generation with no intermixture between parents' genetic material. Mitochondria are small organelles that lie in the cytoplasm of eukaryotic cells, such as those of humans. Their primary function is to provide energy to the cell. Mitochondria are thought to be reduced descendants of symbiotic bacteria that were once free living.

Secondary structure of the human mitochondrial genome affects formation of deletions

Jacques Fellay, Konstantin Popadin, Dmitry Knorre

BackgroundAging in postmitotic tissues is associated with clonal expansion of somatic mitochondrial deletions, the origin of which is not well understood. Such deletions are often flanked by direct nucleotide repeats, but this alone does not fully explain ...

BMC2023

Secondary structure of the human mitochondrial genome affects formation of deletions

Dynamics of the most common pathogenic mtDNA variant m.3243A > G demonstrate frequency-dependency in blood and positive selection in the germline

Cell lineage tracing in human tissues using somatic mitochondrial mutations

Cell lineage tracing in human tissues using somatic mitochondrial mutations

Dynamics of the most common pathogenic mtDNA variant m.3243A > G demonstrate frequency-dependency in blood and positive selection in the germline

Secondary structure of the human mitochondrial genome affects formation of deletions