DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.53060#0207
206
6 Preliminary analyses of DNA in skeletal material from the Harbor Necropolis
to sequence whole genomes in a fraction of time compared to conventional sequencing. A major
advantage with this technology is that through analysing the high number of DNA fragments
preserved in each aliquot of amplified DNA, the degradation of the samples could be evaluated,
giving statistical support to the most likely authentic sequence (e.g. c-statistics; Helgason et al.
2009). Thus, NGS has almost circumvented the always impending danger of contamination from
surrounding material, and has rather introduced computational limitations by the huge amount
of data produced.
6.2 MITOCHONDRIAL DNA
Mitochondrial DNA (mtDNA) is to date the most frequently applied genetic marker system for
investigating the history and origin of human populations. MtDNA, a small, extra-nuclear circu-
lar organelle, has a maternal inheritance mode, meaning that it is transmitted directly, and only,
from mothers to childrens. Unlike genes on the chromosomes, mtDNA has no recombination or
major rearrangements, and mutational events occur relatively often over generations, making
it informative even in a short evolutionary scale. While autosomal DNA is found in only two
copies (on the chromosomes) in each cell, every body cell contains high numbers of mtDNA
copies, a major advantage for investigation of old and degraded biological samples of low DNA
quantity and quality. MtDNA diversity has been thoroughly documented worldwide, making
a large reference material available, both from present and past human populations. However,
mtDNA reflects the female history only, not necessarily the population as a whole. Autosomal
markers (i.e. unisexual genetic markers) reflect the complex mosaic of the genetic history of
all past relatives, while Y-chromosome markers are the male counterpart to mtDNA, providing
information on the paternal history.
Each mtDNA variant, called haplotype, can be classified according to the particular set of
mutations or variable positions found within a sequence stretch of the mtDNA. Sequences with
similar mutation motifs are grouped together in haplogroups, denoted with capital letters. Ancient
human expansions and migrations are reflected in the geographical distributions of haplogroups.
The mtDNA lineages of the world are presented in figure 83. In Africa, the ancestral L-hap-
Human mtDNA Migrations
From http:iAivww.mitomap.org
Symbols +/-, +/+, and represent
RFLP status for Dde 1 10394 / Alu I 10397
Mutation rate = 2.2 - 2.9 % / M YR
Time estimates are YBP
Fig. 83 Worldwide human migrations estimated by mtDNA haplogroups. Time estimates for continent expansions
are given as years before present (YBP) (Foto © <http://www.mitomap.org> [accessed on July 05, 2016])
6 Preliminary analyses of DNA in skeletal material from the Harbor Necropolis
to sequence whole genomes in a fraction of time compared to conventional sequencing. A major
advantage with this technology is that through analysing the high number of DNA fragments
preserved in each aliquot of amplified DNA, the degradation of the samples could be evaluated,
giving statistical support to the most likely authentic sequence (e.g. c-statistics; Helgason et al.
2009). Thus, NGS has almost circumvented the always impending danger of contamination from
surrounding material, and has rather introduced computational limitations by the huge amount
of data produced.
6.2 MITOCHONDRIAL DNA
Mitochondrial DNA (mtDNA) is to date the most frequently applied genetic marker system for
investigating the history and origin of human populations. MtDNA, a small, extra-nuclear circu-
lar organelle, has a maternal inheritance mode, meaning that it is transmitted directly, and only,
from mothers to childrens. Unlike genes on the chromosomes, mtDNA has no recombination or
major rearrangements, and mutational events occur relatively often over generations, making
it informative even in a short evolutionary scale. While autosomal DNA is found in only two
copies (on the chromosomes) in each cell, every body cell contains high numbers of mtDNA
copies, a major advantage for investigation of old and degraded biological samples of low DNA
quantity and quality. MtDNA diversity has been thoroughly documented worldwide, making
a large reference material available, both from present and past human populations. However,
mtDNA reflects the female history only, not necessarily the population as a whole. Autosomal
markers (i.e. unisexual genetic markers) reflect the complex mosaic of the genetic history of
all past relatives, while Y-chromosome markers are the male counterpart to mtDNA, providing
information on the paternal history.
Each mtDNA variant, called haplotype, can be classified according to the particular set of
mutations or variable positions found within a sequence stretch of the mtDNA. Sequences with
similar mutation motifs are grouped together in haplogroups, denoted with capital letters. Ancient
human expansions and migrations are reflected in the geographical distributions of haplogroups.
The mtDNA lineages of the world are presented in figure 83. In Africa, the ancestral L-hap-
Human mtDNA Migrations
From http:iAivww.mitomap.org
Symbols +/-, +/+, and represent
RFLP status for Dde 1 10394 / Alu I 10397
Mutation rate = 2.2 - 2.9 % / M YR
Time estimates are YBP
Fig. 83 Worldwide human migrations estimated by mtDNA haplogroups. Time estimates for continent expansions
are given as years before present (YBP) (Foto © <http://www.mitomap.org> [accessed on July 05, 2016])
