A ghost population is a population that has been inferred through using statistical techniques. [1]
In 2004, it was proposed that maximum likelihood or Bayesian approaches that estimate the migration rates and population sizes using coalescent theory can use datasets which contain a population that has no data. This is referred to as a "ghost population". The manipulation allows exploration in the effects of missing populations on the estimation of population sizes and migration rates between two specific populations. The biases of the inferred population parameters depend on the magnitude of the migration rate from the unknown populations. [1] The technique for deriving ghost populations attracted criticism because ghost populations were the result of statistical models, along with their limitations. [2]
In 2012, DNA analysis and statistical techniques were used to infer that a now-extinct human population in northern Eurasia had interbred with both the ancestors of Europeans and a Siberian group that later migrated to the Americas. The group was referred to as a ghost population because they were identified by the echoes that they leave in genomes—not by bones or ancient DNA. [3] In 2013, another study found the remains of a member of this ghost group, fulfilling the earlier prediction that they had existed. [4] [5]
According to a study published in 2020, there are indications that 2% to 19% (or about ≃6.6 and ≃7.0%) of the DNA of four West African populations may have come from an unknown archaic hominin which split from the ancestor of humans and Neanderthals between 360 kya to 1.02 mya. However, the study also suggests that at least part of this archaic admixture is also present in Eurasians/non-Africans, and that the admixture event or events range from 0 to 124 ka B.P, which includes the period before the Out-of-Africa migration and prior to the African/Eurasian split (thus affecting in part the common ancestors of both Africans and Eurasians/non-Africans). [6] [7] [8] Another recent study, which discovered substantial amounts of previously undescribed human genetic variation, also found ancestral genetic variation in Africans that predates modern humans and was lost in most non-Africans. [9]
In 2015, a study of the lineage and early migration of the domestic pig found that the best model that fitted the data included gene flow from a ghost population during the Pleistocene that is now extinct. [10]
A 2018 study suggests that the common ancestor of the wolf and the coyote may have interbred with an unknown canid related to the dhole. [11]
Early modern human (EMH), or anatomically modern human (AMH), are terms used to distinguish Homo sapiens that are anatomically consistent with the range of phenotypes seen in contemporary humans, from extinct archaic human species. This distinction is useful especially for times and regions where anatomically modern and archaic humans co-existed, for example, in Paleolithic Europe. Among the oldest known remains of Homo sapiens are those found at the Omo-Kibish I archaeological site in south-western Ethiopia, dating to about 233,000 to 196,000 years ago, the Florisbad site in South Africa, dating to about 259,000 years ago, and the Jebel Irhoud site in Morocco, dated about 315,000 years ago.
Genetics and archaeogenetics of South Asia is the study of the genetics and archaeogenetics of the ethnic groups of South Asia. It aims at uncovering these groups' genetic histories. The geographic position of the Indian subcontinent makes its biodiversity important for the study of the early dispersal of anatomically modern humans across Asia.
Human genetic variation is the genetic differences in and among populations. There may be multiple variants of any given gene in the human population (alleles), a situation called polymorphism.
David Emil Reich is an American geneticist known for his research into the population genetics of ancient humans, including their migrations and the mixing of populations, discovered by analysis of genome-wide patterns of mutations. He is professor in the department of genetics at the Harvard Medical School, and an associate of the Broad Institute. Reich was highlighted as one of Nature's 10 for his contributions to science in 2015. He received the Dan David Prize in 2017, the NAS Award in Molecular Biology, the Wiley Prize, and the Darwin–Wallace Medal in 2019. In 2021 he was awarded the Massry Prize.
Peștera cu Oase is a system of 12 karstic galleries and chambers located near the city Anina, in the Caraș-Severin county, southwestern Romania, where some of the oldest European early modern human (EEMH) remains, between 42,000 and 37,000 years old, have been found.
Early human migrations are the earliest migrations and expansions of archaic and modern humans across continents. They are believed to have begun approximately 2 million years ago with the early expansions out of Africa by Homo erectus. This initial migration was followed by other archaic humans including H. heidelbergensis, which lived around 500,000 years ago and was the likely ancestor of Denisovans and Neanderthals as well as modern humans. Early hominids had likely crossed land bridges that have now sunk.
A ghost lineage is a hypothesized ancestor in a species lineage that has left no fossil evidence, but can still be inferred to exist or have existed because of gaps in the fossil record or genomic evidence. The process of determining a ghost lineage relies on fossilized evidence before and after the hypothetical existence of the lineage and extrapolating relationships between organisms based on phylogenetic analysis. Ghost lineages assume unseen diversity in the fossil record and serve as predictions for what the fossil record could eventually yield; these hypotheses can be tested by unearthing new fossils or running phylogenetic analyses.
In paleoanthropology, the recent African origin of modern humans or the "Out of Africa" theory (OOA) is the most widely accepted model of the geographic origin and early migration of anatomically modern humans. It follows the early expansions of hominins out of Africa, accomplished by Homo erectus and then Homo neanderthalensis.
The Denisovans or Denisova hominins(di-NEE-sə-və) are an extinct species or subspecies of archaic human that ranged across Asia during the Lower and Middle Paleolithic. Denisovans are known from few physical remains; consequently, most of what is known about them comes from DNA evidence. No formal species name has been established pending more complete fossil material.
Population genetics research has been conducted on the ancestry of the modern Turkish people in Turkey. Such studies are relevant for the demographic history of the population as well as health reasons, such as population specific diseases. Some studies have sought to determine the relative contributions of the Turkic peoples of Central Asia, from where the Seljuk Turks began migrating to Anatolia after the Battle of Manzikert in 1071, which led to the establishment of the Anatolian Seljuk Sultanate in the late 11th century, and prior populations in the area who were culturally assimilated during the Seljuk and the Ottoman periods.
Interbreeding between archaic and modern humans occurred during the Middle Paleolithic and early Upper Paleolithic. The interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.
In archaeogenetics, the term Ancient North Eurasian (ANE) is the name given to an ancestral component that represents the lineage of the people of the Mal'ta–Buret' culture (c. 24,000 BP) and populations closely related to them, such as the Upper Paleolithic individuals from Afontova Gora in Siberia. Genetic studies indicate that the ANE are closely related to the Ancient North Siberians (ANS) represented by two ancient specimens from the preceding Yana Culture (c. 32,000 BP). The ANE can either be considered to descend from the earlier ANS population, or that both ANE and ANS are closely related, albeit differentiated, sister lineages, which both originated from a merger of 'Early West Eurasian' hunter-gatherers (represented by Kostenki-14, c. 40,000 BP), and an 'Early East Eurasian' population. Both the ANE and the ANS derive around 1/3 of their ancestry from Early East Eurasian lineages, and around 2/3 from Early West Eurasian lineages.
Early European Farmers (EEF), First European Farmers (FEF), Neolithic European Farmers, Ancient Aegean Farmers, or Anatolian Neolithic Farmers (ANF) are names used to describe a distinct group of early Neolithic farmers who brought agriculture to Europe and Northwest Africa (Maghreb). Although the spread of agriculture from the Middle East to Europe has long been recognised through archaeology, it is only recent advances in archaeogenetics that have confirmed that this spread was strongly correlated with a migration of these farmers, and was not just a cultural exchange.
Genetic studies on Neanderthal ancient DNA became possible in the late 1990s. The Neanderthal genome project, established in 2006, presented the first fully sequenced Neanderthal genome in 2013.
Denny is a ~90,000 year old fossil specimen belonging to a ~13-year-old Neanderthal-Denisovan hybrid girl. To date, she is the only first-generation hybrid hominin ever discovered. Denny’s remains consist of a single fossilized fragment of a long bone discovered among over 2,000 visually unidentifiable fragments excavated at the Denisova Cave in the Altai Mountains, Russia in 2012.
Basal Eurasian is a proposed lineage of anatomically modern humans with reduced, or zero, archaic hominin (Neanderthal) admixture compared to other ancient non-Africans. Basal Eurasians represent a sister lineage to other Eurasians and may have originated from the Southern Middle East, specifically the Arabian peninsula, or North Africa, and are said to have contributed ancestry to various West Eurasian, South Asian, and Central Asian groups. This hypothetical population was proposed to explain the lower archaic admixture among modern West Eurasians compared to with East Eurasians, although alternatives without the need of such Basal lineage exist as well.
Eukaryote hybrid genomes result from interspecific hybridization, where closely related species mate and produce offspring with admixed genomes. The advent of large-scale genomic sequencing has shown that hybridization is common, and that it may represent an important source of novel variation. Although most interspecific hybrids are sterile or less fit than their parents, some may survive and reproduce, enabling the transfer of adaptive variants across the species boundary, and even result in the formation of novel evolutionary lineages. There are two main variants of hybrid species genomes: allopolyploid, which have one full chromosome set from each parent species, and homoploid, which are a mosaic of the parent species genomes with no increase in chromosome number.
The genetic history of Africa is composed of the overall genetic history of African populations in Africa, including the regional genetic histories of North Africa, West Africa, East Africa, Central Africa, and Southern Africa, as well as the recent origin of modern humans in Africa. The Sahara served as a trans-regional passageway and place of dwelling for people in Africa during various humid phases and periods throughout the history of Africa.
Basal West African is a hypothetical line of descent that is no longer extant.
The term Ancient East Eurasian, alternatively also known as East Eurasian or Eastern Eurasian, is used in population genomics to describe the genetic ancestry and phylogenetic relationship of diverse populations primarily living in the Asia-Pacific region, belonging to the "Eastern Eurasian clade" of human genetic diversity, and which can be associated with the Initial Upper Paleolithic (IUP) wave, following the Out of Africa migration (>60kya).