Archaeogenetics
Archaeogenetics provides us with genetic evidence of ancient population group migrations,[1] domestication events, and plant and animal evolution.
[5] In February 2021, scientists reported the oldest DNA ever sequenced was successfully retrieved from a mammoth dating back over a million years.
[8] A majority of his work was researching the links of blood types to sex, disease, climate, age, social class, and race.
His work provided the foundation for archaeogenetics because it facilitated the separation of genetic evidence for biological relationships between people.
However, there are more ways to discover excavation zones using technology such as field portable x-ray fluorescence[15] and Dense Stereo Reconstruction.
Moreover, DNA preservation is also affected by other factors such as the treatment of the unearthed fossil like (e.g. washing, brushing and sun drying), pH, irradiation, the chemical composition of bone and soil, and hydrology.
[20] One of the more common methods utilizes silica and takes advantage of polymerase chain reactions in order to collect ancient DNA from bone samples.
To avoid contamination it is necessary to take many precautions such as separate ventilation systems and workspaces for ancient DNA extraction work.
[23] Coming to a consensus on which methods are best at mitigating challenges is also difficult due to the lack of repeatability caused by the uniqueness of specimens.
[25] Some issues with PCR is that it requires overlapping primer pairs for ancient DNA due to the short sequences.
This is generally more costly and time intensive than PCR but due to the difficulties involved in ancient DNA amplification it is cheaper and more efficient.
[25] One method of massive parallel sequencing, developed by Margulies et al., employs bead-based emulsion PCR and pyrosequencing,[27] and was found to be powerful in analyses of aDNA because it avoids potential loss of sample, substrate competition for templates, and error propagation in replication.
For example, the American indigenous population is characterized by specific mitochondrial RFLPs and deletions defined by Wallace et al.[30] aDNA comparison study can also reveal the evolutionary relationship between two species.
[26] The phylogeny of some extinct species, such as Australian marsupial wolves and American ground sloths, has been constructed by this method.
Scholz et al. conducted southern blot hybridization on Neanderthal aDNA (extracted from fossil remain W-NW and Krapina).
This is always done by mapping aDNA sequence onto the karyotype of a well-studied closely related species, which share a lot of similar phenotypic traits.
[28] Other similar studies include finding of a mutation associated with dwarfism in Arabidopsis in ancient Nubian cotton,[29] and investigation on the bitter taste perception locus in Neanderthals.
[32] Analysis of mtDNA shows that modern humans occupied Eurasia in a single migratory event between 60 and 70 kya.
[34] Cavalli-Svorza's analysis of genetic-geographic patterns led him to conclude that there was a massive influx of Near Eastern populations into Europe at the start of the Neolithic.
[34] Most “control-region lineages” of modern European mtDNA are traced to a founder event of reoccupying northern Europe towards the end of the Last Glacial Maximum (LGM).
[34] South Asia has served as the major early corridor for geographical dispersal of modern humans from out-of-Africa.
[36] The Pan-Asian SNP (single nucleotide polymorphism) study found “a strong and highly significant correlation between haplotype diversity and latitude,” which, when coupled with demographic analysis, supports the case for a primarily south-to-north occupation of East Asia.
[37] Although the most widely held theory suggests “three waves” of migration after the LGM through the Bering Strait, genetic data have given rise to alternative hypotheses.
[37] Y-chromosome data has led some to hold that there was a single migration starting from the Altai Mountains of Siberia between 17.2 and 10.1 kya, after the LGM.
[37] Analysis of both mtDNA and Y-chromosome DNA reveals evidence of “small, founding populations.”[37] Studying haplogroups has led some scientists to conclude that a southern migration into the Americas from one small population was impossible, although separate analysis has found that such a model is feasible if such a migration happened along the coasts.
[38] Together, NRY and mtDNA studies show that the splitting event between the two groups was over 50 kya, casting doubt on recent common ancestry between the two.
[39] Findings in crop 'domestication genes' (traits that were specifically selected for or against) include Through the study of archaeogenetics in plant domestication, signs of the first global economy can also be uncovered.
The geographical distribution of new crops highly selected in one region found in another where it would have not originally been introduced serve as evidence of a trading network for the production and consumption of readily available resources.
[40] The information gained from genetics studies on current populations helps guide the Archaeologist's search for documenting these ancestors.
[42] Archaeological findings help better understand this complicated past by providing solid evidence about the progression of the domestication of dogs.
