A genetic isolate is population of organisms that has little genetic mixing with other organisms within the same species. This may result in speciation

Speciation

Speciation is the evolutionary process by which new biological species arise. The biologist Orator F. Cook seems to have been the first to coin the term 'speciation' for the splitting of lineages or 'cladogenesis,' as opposed to 'anagenesis' or 'phyletic evolution' occurring within lineages...

, but this is not necessarily the case. Genetic isolates may form new species in several ways:

• allopatric speciation
  Allopatric speciation
  Allopatric speciation or geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration...
  
  , in which two populations of the same species are geographically isolated from one another by an extrinsic barrier, and evolve intrinsic (genetic) reproductive isolation
• peripatric speciation
  Peripatric speciation
  Peripatric and peripatry are terms from biogeography, referring to organisms whose ranges are closely adjacent but do not overlap, being separated where these organisms do not occur – for example a wide river or a mountain range. Such organisms are usually closely related Peripatric and...
  
  , in which a small group of a population is separated from the main population, and experiences genetic drift
  Genetic drift
  Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
  
  
• parapatric speciation
  Parapatric speciation
  Parapatry is a term from biogeography, referring to organisms whose ranges do not significantly overlap but are immediately adjacent to each other; they only occur together in the narrow contact zone, if at all. This geographical distribution is opposed to sympatry & allopatry or peripatry...
  
  , in which zones of two diverging populations are separate, but do overlap somewhat; partial separation is afforded by geography, so individuals of each species may come in contact from time to time, but selection for specific behaviours or mechanisms may prevent breeding between the two groups.
• sympatric speciation
  Sympatric speciation
  Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap or are even identical, so that...
  
  , a contentious method of speciation in which species diverge while inhabiting the same place.

Human-influences on genetic isolates include restricted breeding of dogs

Dog breeding

Dog breeding is the practice of mating selected specimens with the intent to maintain or produce specific qualities and characteristics.Dogs reproduce without human interference, so their offsprings' characteristics are determined by natural selection. Domestic dogs may be intentionally bred by...

, or a community living secluded away from others (such as Tristan da Cunha

Tristan da Cunha

Tristan da Cunha is a remote volcanic group of islands in the south Atlantic Ocean and the main island of that group. It is the most remote inhabited archipelago in the world, lying from the nearest land, South Africa, and from South America...

 or Pitcairn Islands

Pitcairn Islands

The Pitcairn Islands , officially named the Pitcairn, Henderson, Ducie and Oeno Islands, form a group of four volcanic islands in the southern Pacific Ocean. The islands are a British Overseas Territory and overseas territory of the European Union in the Pacific...

). A far larger and less secluded human genetic isolate is the ethnic Finns, natives of Finland

Finland

Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

 (see Finnish disease heritage).