Lineage (genetic)

A genetic lineage also known as genetic pedigree is a series of mutations which connect an ancestral genetic type (allele, haplotype, or haplogroup) to derivative type.[1] In cases where the genetic tree is very bushy the order of mutations in the lineage is mostly known, examples are the order of mutations between E1b1b and E1b1b1a1a for the human Y-chromosomesal L0 or L1 nodes.[2]

A genetic lineage can be contrasted with an evolutionary lineage in that a genetic lineage applies to a locus. An example of the difference is that an ancient African ape evolved into the gorilla-chimpanzee-human ancestor, which further evolved into the chimpanzee-human ancestor and then to humans. While most human lineages coalesce with chimpanzee lineages, which then converge with gorilla lineages, a few human lineages coalesce with gorilla lineages and then converge with chimpanzee lineages (or chimpanzee lineages that coalesce with gorilla lineages and then converge with human lineages). This occurs because speciation splits evolutionary lineages in non-discrete events that involve 10s to 10000s of individuals in each developing taxon. This allows multiple deeply rooted lineages to be passed on for millions of years (See 2N-rule; 2 * 20 year/generations * 10,000 inds * ploidy), over two or more speciation events. Such lineages may randomly undergo fixation at any time.

Basal lineage

In genetics a basal lineage is a genetic lineage that connects a variant allele (type) possessed by a more common ancestor that evolves into two descendant variants possessed by a branch ancestor. An example of a basal lineage is the lineage between mitochondrial 'Eve' and L0 or L1. Basal lineages may have types that are no longer represented in the extant population, only being defined by derivative types such as CRS for L1.

Peripheral lineage

Peripheral lineage (also surface lineage) are lineages in which interconnect an extant type to a branch ancestor.

References
  1. "The Genographic Project - Human Migration, Population Genetics, Maps, DNA - National Geographic".
  2. Gonder, MK; Mortensen, HM; Reed, FA; de Sousa, A; Tishkoff, SA (December 2007), "Whole-mtDNA genome sequence analysis of ancient African lineages", Mol. Biol. Evol., 24 (3): 757–68, doi:10.1093/molbev/msl209, PMID 17194802
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