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Chapter 10
Who Were the Nasca? Population Dynamicsin Pre-Columbian Southern Peru Revealedby Ancient DNA Analyses
Lars Fehren-Schmitz, Susanne Hummel and Bernd Herrmann
Abstract Through the analysis of ancient DNA from human mortal remains
it is possible to gain access to a biohistoric archive containing relevantinformation about the structure of prehistoric populations. The data
obtained help to answer questions related to migration processes and popu-
lation relationships that could not be answered by the methods of cultural
science alone. The aim of this study was to show to what extent the cultural
evolution of the southern Peruvian Palpa area was accompanied by processes
of population exchange. Bone and tooth samples of over 200 individuals from
prehistoric burial grounds from southern Peru were collected and examined
with the methods of ancient DNA analysis. The study focuses on the matri-
lineal population dynamics by the analysis of mitochondrial genetic markers.Mitochondrial haplogroups and types could be successfully determined for
over 100 individuals from different archaeological periods. The obtained
data were compared with mitochondrial data from recent Native American
populations. The results allow us to describe to what extent cultural changes
were influenced by allochthonous contributions to the gene pool and how
changes in the socioecological complexity of the cultures affected the genetic
composition of the Palpa valley population. Also, a significant differentia-
tion of ancient coastal and highland populations in southern Peru is detect-
able as are changes in the mitochondrial haplogroup distribution patterns asa result of the emergence of the extensive highland empires in later South
American prehistory.
L. Fehren-Schmitz (*)
Johann Friedrich Blumenbach Institute of Zoology and Anthropology, HistoricalAnthropology and Humanecology, Georg-August-University Goettingen,
Bu rgerstrae50, 37073 Gottingen, Germany
e-mail: [email protected]
M. Reindel, G.A. Wagner (eds.), New Technologies for Archaeology,
Natural Science in Archaeology, DOI 10.1007/978-3-540-87438-6_10,
Springer-Verlag Berlin Heidelberg 2009
159
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10.1 Introduction
One of the recurrent questions of archaeological science is how far cultural
change in a geographic region is connected to changes in the biological popula-
tion structure, for example, by migration. The progression of archaeologicaltheories from cultural history, processual archaeology, and postprocessual
archaeology to the present developments were always accompanied by changes
in the perception of migration as a potential factor in cultural evolution
(Anthony 1990). There are many possible scenarios for the cause of cultural
changes reaching from pure autochthonous developments or cultural diffusion
with a stable population to culture change through population replacements by
processes of migration or invasion (Burmeister 2000). Although changes in the
material culture can be detected in the archaeological record by typological
comparison, methods of cultural science allow no definite decision if new craftstyles, ritual behavior, and so on were introduced by immigrating people or
other mechanisms of diffusion. The only archive that can be used to resolve this
question is humans themselves.
Through the use of molecular genetic methods it is possible to gain access to
a nonbiographic archive containing all relevant information about the biologi-
cal composition of a population. Uniparental inherited genetic markers such
as mitochondrial DNA (mtDNA) and the nonrecombining proportion of the
Y-chromosome (nryDNA) have proven valuable for the reconstruction of the
global spread of Homo sapiens and therewith the understanding of longerterm global patterns of human diversification (Underhill and Kivisild 2007).
Analyses of the maternal inherited mtDNA and paternal inherited nryDNA
from recent populations were successfully used to throw light on the processes
source populations, number of migrants, migration dates, routes, and so on
accompanying the initial colonisation of the Americas (e.g., Torroni et al.
1993), Europe (e.g., Richards et al. 1998), and Australia (e.g., Hudjashov
et al. 2007). Comparisons of the data from both genetic markers also allowed
the analysis of sex-specific mobility patterns and therewith human migrational
behavior (e.g., Wilder et al. 2004). All those studies use DNA from recentpopulations to reconstruct historic migration processes by utilising methods
and calculations of population genetics.
Through the development of methods and techniques to analyse ancient
DNA (aDNA) from pre-/historic specimen physical anthropology gained an
analytic tool that also allows the access to such genetic data from populations
and cultures that vanished long ago. Instead of deducing historic processes
from a recent genetic as-is state, these methods allow a diachronic comparison
of the genetic relationship of ancient populations. Furthermore the analysis of
ancient DNA allows, for example, the reconstruction of complex genealogiesfrom individuals buried in prehistoric burial grounds as shown for the Bronze
Age Lichtenstein Cave near Osterode, Germany (Schilz 2006) or species deter-
mination from prehistoric animal remains (Renneberg et al. this volume).
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To conduct such investigations, methods and techniques developed for the
analysis of DNA from living organisms have to be adapted to the specific
characteristics of aDNA, DNA degradation patterns have to be examined,
and methods of contamination control and prevention have to be improved.
So the constant development of new methods and techniques is an essentialneed for palaeogenetic science. Detailed information on possible applications,
methods, specifics, and possible problems faced with the analysis of aDNA are
compiled in some review articles (e.g., Paabo et al. 2004; Willerslev and Cooper
2005) and two monographs published by the Palaeogenetics Group of the
Department of Historic Anthropology, Gottingen (Herrmann and Hummel
1995; Hummel 2003).
10.1.1 The Peopling of South America from a Genetic Perspective
Important insights into the initial colonisation of the New World have been
gained through molecular genetic studies particularly through the analyses of
mtDNA of recent Asian and Native American populations. Today it is gen-
erally agreed that the first humans entered the Americas through or along the
Beringian land bridge. Controversy arises when it comes to the timing, the precise
route, and the number of major migrations. The most parsimonious model by
todays state of knowledge from genetic data is a single initial migration withrelatively few individuals about 20,00014,000 years ago along a Pacific coastal
route (Merriwether et al. 1995; Silva et al. 2002; Schurr 2004; Lewis et al. 2007).
The assumption of rapid spread of the people along the Pacific coast from
Beringia to southernmost South America and therewith a pre-Clovis colonisation
of the Americas is consistent with archaeological data (Dixon 2001) and the
assured early 14C dates of South American archaeological contexts such as
Monte Verde, Chile (Dillehay 1999). Demographic simulations also prove that
even for a small founding population by this route it would be possible to cover
such a distance Alaska to Tierra del Fuego in relatively short time (e.g., 1000
years) under retention of an effective population size (Fix 2002).
Despite the richness of their cultures and the richness of environments that
they inhabit, the Native Americans harbor a low level of genetic diversity. This
is probably a consequence of the previously described terms of the initial
peopling. Nearly all Native American mtDNA-haplotypes belong to four
ancestral lineages, the mt-haplogroups labled A, B, C, and D (Torroni et al.
1993). These lineages are widely found throughout the Americas, but there is a
lot of variation in frequencies among populations and geographic regions.
A fifth founding mitochondrial haplogroup, designated X, is only found in
indigenous populations of northern North America (Dornelles et al. 2005). All
of those five major matrilineages (mt-haplogroups) were represented by only
one (Schurr 2004) or a few (Tamm et al. 2007) sublineages (mt-haplotypes) in
the initial founding population. The mt-haplogroups have a definite Asian
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ancestry and the genetic data indicate that the ancestral source population
probably originated in south-central Siberia from where it migrated to Beringia
and then into the New World (Schurr 2004).
In the case of the Y-chromosomal DNA most male Native Americans belong
to the two principal founding lineages C and Q (nomenclature: Y-ChromosomeConsortium 2002). Haplogroup Q dominates with about 75% and for South
America especially the subhaplogroup Q-M3 can be found, a group not existent
outside the Americas (Underhill et al. 2001).
Although understanding of the further peopling of North America has
significantly progressed in the last years this is not the case for South America.
There is compelling archaeological and genetic evidence to suggest that the
continent was peopled by 1413,000 years ago (Dillehay 1999; Fuselli et al.
2003) but there is no agreement regarding the number of initial migrations and
the migration routes (Lalueza et al. 1997; Rothhammer et al. 2001; Keyeux et al.2002; Lewis et al. 2007). South America has a unique pattern of genetic diver-
sity. Western (Andean) populations show a higher level of within-population
diversity but short genetic distances to each other when compared to eastern
(Amazonian) populations (Fuselli et al. 2003; Lewis et al. 2005).
There is a very specific regional distribution of mitochondrial haplogroup
frequencies (Fig. 10.1; Fehren-Schmitz 2008) and a high frequency of mt-
Haplotypes that are unique and not shared between different regions. Recent
genetic comparison of modern Native American populations from all over
South America based on mitochondrial Hyper Variable Region I (HVR I)sequences show that although there are regional differences in the patterns of
genetic variation the low overall variance among these regions gives no evidence
for several migrational waves (Lewis et al. 2007). Even if this makes it most
parsimonious that the continent was peopled by one founding population, the
exact routes, and if this wave split in different groups when passing the Isthmus
of Panama remains uncertain. This lack of knowledge partly can be attributed
to the circumstance that all available hypotheses regarding these questions are
based on the analysis of recent Native American populations. There are only a
few aDNA studies from South America with reliable results (e.g., Shimada et al.2004; Moraga et al. 2005; Shinoda et al. 2006). Unfortunately most of these
studies have neither a sample size that allows relevant population genetic
calculations nor diachronic developments of settlement areas. The palaeogentic
investigations conducted within the NascaPalpa project are the first large-
scale, diachronic aDNA studies for South America.
10.1.2 Aims and Goals of the Palaeogenetic Investigations
of Human Remains from the Palpa Area
One of the aims of the study presented here was to prove that large-scale ancient
DNA investigations can be used to reveal complex population dynamics in
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prehistoric settlement areas, and prove the existence of migration processes and
their influences on culture as well as cultural influence on migration patterns.
The Palpa area in southern Peru and the scientific conditions of the Nasca
Palpa project offered the perfect conditions for such investigations. The archae-
ological evidence shows settlement continuity for this area until now, beginning
with the Archaic period (about 3800 BC). In this long period of time the region
faced many more or less dramatic cultural changes and the emergence anddisappearance of archaeological cultures such as the Paracas and Nasca
(Reindel this volume). The new insights into the cultural and ecological history
of the southern Peruvian coast that arose from the project at the same time
Fig. 10.1 Recent regional distribution of mitochondrial haplogroup frequencies in native
South American populations. For this illustration a reduced dataset is used. Refer to
Fehren-Schmitz (2008) for a more detailed distribution map. (Data used: Torroni et al.
1993; Merriwether et al. 1995; Ward et al. 1996; Rickards et al. 1999; Moraga et al. 2000;Goicoechea et al. 2001; Keyeux et al. 2002; Fuselli et al. 2003; Lewis et al. 2005; Torres et al.
2006; Garcia et al. 2006; Lewis et al. 2007)
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raised new questions regarding population relationships and population dis-
continuities or continuities, for instance:
Was the Paracas tradition in southern Peru represented by a biological
uniform population or by solitary local groups sharing cultural traits(Silverman and Proulx 2002)? Did the Nasca culture evolve from the Paracas tradition with a continuous
population? Or was it introduced to the region by foreign culture-bearers? Are there any biological traces of Wari influence in the Palpa region at the
end of the Nasca period that justify the assumption of invasion or elite-
dominance scenarios as formulated by Allison (1979)?
In addition to those questions that focus on the regional population
dynamics in southern Peru the investigations should help to shed light on the
peopling of western South America.As mentioned above there is a constant need for fundamental research, for
example, to understand the degradation processes of DNA and to enhance
the methods of authentication and contamination prevention. To answer the
content-related questions new molecular assays had to be developed. For
instance, real-time PCR technology was adapted to the specific requirements
of aDNA research in the course of this project. The adoption of this technology
and thereby development of new methods for low-copy DNA quantification
and inhibition control (Westenthanner et al. in prep) allowed novel insights to
differential DNA preservation in human bones (Fehren-Schmitz 2008) and bychromosomal topography. Additionally real-time PCR technology was used to
develop new, faster SNP (single nucleotide polymorphism) detection assays for
mitochondrial and Y-chromosomal haplogroup determination, allowing high-
throughput analysis for aDNA.
10.2 Material and Methods
10.2.1 Molecular Genetic Markers and Analysis Systems
The studies presented here where mainly based on the analysis of mtDNA, and
therewith the matrilinear population dynamics. Mitochondrial DNA is a cir-
cular double-stranded molecule present in the mitochondria of eukaryotic cells.
Each cell contains hundreds to thousands of copies of mtDNA making it much
more likely that even after the DNA has undergone degradation processes
following death there are more mitochondrial DNA fragments preserved in
human skeletal remains than chromosomal DNA. MtDNA is exclusively
maternally inherited, lacks recombination, and evolves faster than chromoso-
mal DNA (Pakendorf and Stoneking 2005). These characteristics enable us to
trace related maternal lineages nearly unchanged back through time and make
it the molecule of choice for phylogenetic and population genetic studies, most
notably when analysing aDNA.
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To determine the mitochondrial haplotypes we analysed a 388 bp fragment
of the mitochondrial HVR I (np1602116408). A modular analysis system
consisting of eight primers generating overlapping PCR products was designed.
The modular character of this system allows the amplification of fragments
with different sizes: long (434 bp), medium (236261 bp), and short(157180 bp). Therewith it is possible to adapt the analysis to the specific
DNA degradation grades encountered in different samples. The generated
PCR products were further analysed by direct sequencing.
In addition to the determination of the mitochondrial haplogroups by the
specific HVR I polymorphisms we analysed four specific polymorphisms of the
mitochondrial coding region determining the groups A, B, C, and D (Fig. 10.2).
Three of the groups A, C, and D are characterised by SNPs (single base
transversions or transitions) and group B is characterised through a 9 bp deletion
at nucleotide position (np) 82728280 of the mitochondrial genome (Merriwetheret al. 1995). This twofold determination system for mt-haplogroups was devel-
oped to authenticate the results because possible fast-evolving mutational hot-
spots of the HVR I and miscoding lesions caused by postmortem DNA damage
exhibit a high risk of false determinations (Meyer et al. 1999; Willerslev and
Cooper 2005; Gilbert et al. 2007). For the analysis of the four coding region
polymorphisms a hybridisation probe-based multiplex PCR assay for the real-
time PCR was developed. The mitochondrial HybProbe multiplex PCR on the
LightCycler 2.0TM (Roche) allows the simultaneous amplification and determi-
nation (by melting curves analysis) of all four polymorphisms characterising the
Fig. 10.2 Schematic representation of the human mitochondrial DNA genome with thelocation of the three base substitutions and the 9 bp deletion determining the Native American
haplogroups. For each haplogroup the nucleotide position (e.g., np 663) and realised base
substitution (e.g., A) is mentioned. The labels inside the circle specify the respective functional
region (genes) of the mitochondrial genome
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four Native American mt-haplogroups. Conventional methods used to determine
such polymorphisms consist of several analysis steps and therewith are more
time-consuming whereas the developed assay is a one-step procedure.
In addition to the mt-haplogroups/-types also investigations on Y-chromosomal
haplogroups were made. The Y-haplogroups are also characterised by SNPs(cf. Y-Chromosome Consortium 2002). A HybProbe multiplex assay for the real-
time PCR was developed to determine the four most frequently occurring
Y-chromosomal haplogroups in Native American populations: C, P, Q, and Q3
(as mentioned above). SNPs analysed were M130 (C>T) for C, M45 (G>A) for P,
M242 (C>T) for Q, and M3 (C>T) for haplogroup Q3. All analysis systems were
tested on modern DNA from European and South American peoples first before
being applied to the aDNA analysis.
For all analysed populations standard genetic diversity indices were calcu-
lated (Tajima 1993; Nei 1987). Genetic distances between the populations werecalculated on haplogroup and haplotype level. Calculations for the measures
were performed using the Arlequin software package (version 3.1, Excoffier and
Schneider 2005). The obtained HVR I sequence data were also used to calculate
distance-based phylogenetic trees and mean nucleotide distances between popu-
lations by the Mega 4.0 software (Tamura et al. 2007).
10.2.2 Sample Material and Sample Preparation
In different field campaigns (20042006) bone and teeth samples from 216
skeletonised or mummified human individuals were collected (Fig. 10.3). 172
of these were from different archaeological sites in the Palpa area and 44
individuals were from pre-Columbian burial grounds outside this area: Monte
Grande (near the coast to the west of Palpa); Paracas Peninsula (Paracas
Fig. 10.3 Skulls of three human individuals from different archaeological sites of the Palpa
area (left: Los Molinos; right: Pernil Alto) showing the encountered average state of macro-
scopic preservation. Individuals are largely skeletonised with some soft tissue conservation
through mummification
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Cavernas 6), and Pacapaccari (Andean highlands to the east of Palpa). The
Palpa samples were collected from chronologically varying sites so that it was
possible to investigate a timeframe from the late Archaic period (approx. 3800
BC) to the Middle Horizon (6501000 AD). Sites bearing burials from more
than one archaeological phase were preferred. Sampled sites, their chronologi-cal classifications, and the number of individuals sampled from them for each
chronological period are listed in Table 10.1.
Sample preparation for DNA extraction followed a standardised protocol
(Hummel 2003). Bone and teeth fragments were mechanically pulverised and
afterwards chemical procedures for decalcification and cellysation of the bone-
powder followed. Automated DNA extraction and purification were performed
with an EZ1 Biorobot (Qiagen). For each sample two or more extracts were
made. This precaution allows an authentication of analysis results by compar-
ison (Hummel 2003).In addition to the aDNA investigations, mt-haplogroup (cf. Fig. 10.1) and
HVR I sequence data of over 4000 Native American individuals from different
South American populations were collected from the literature to compare the
pre-Columbian Palpa populations with the whole continent. Only a part of the
obtained data and comparisons is presented here. For further information
concerning the used extraction methods, primer sequences, analysis para-
meters, and statistic parameters, for example, refer to Fehren-Schmitz (in
prep.). In the context of this text it is only possible to present a fractional
Table 10.1 Distribution of individuals sampled (number) tabulated by site and dating
Period / Culture Phase PernilAlto
Mollake
Chico
Jauranga
LosMolinos
LaMuna
Hanaq
Pacha
Monte
Grande
Paracas
Peninsula
Pacapa-
ccari
LIP 8
16
MH
1
5 2
LATE
MIDDLE
7
19
821
NASCA
EARLY15
4
27
LATE
MIDDLE12
48
PARACAS
EARLY 510
INITIALPERIOD
1ARCHAIC PERIOD
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amount of all generated genetic data, used datasets, population statistics, and
other details of the conducted studies.
10.3 Results and Interpretation
10.3.1 Molecular Analysis Results and Data Evaluation
Despite recently formulated hypotheses that the ecological conditions of desert
environments allow a maximum preservation time for DNA of approximately
700 years (e.g., Marota et al. 2002) the methods used and developed in the
context of this study proved successful in the recovery of DNA from much older
bone material stored in desert soils. Overall it was possible to reproduciblydetermine the mt-haplogoups of 131 individuals and mt-haplotypes (complete
388 bp HVR I sequence) of 105 individuals. Amplification of Y-chromosomal
DNA was only successful for six individuals (all Y-haplogroup Q-M3), five
from the site Pacapaccari (Andean highlands) and one from Jauranga (Palpa).
Generally it can be stated that the grade of DNA preservation found in the
individuals of the highland Chullpas proved to be better than in the individuals
from desert burials. The stable level of humidity and temperature encountered
in the Chullpas can be best compared to storage conditions in caves, which
proved to be very good for DNA preservation (Burger et al. 1999). The poorerDNA preservation in the Palpa area may be explained by higher temperature
and soil pH-value, but also the chronologically changing environmental condi-
tions (Eitel and Ma chtle 2006) and therewith storage conditions of the region.
For population statistics the data obtained from the different archaeological
sites were grouped by time period and region (e.g., ParacasPalpa and Paracas
Paracas Peninsula). For the Nasca period two extra divisions were made based on
the socioeconomic character of the sites with which the individuals were asso-
ciated. Individuals from Los Molinos and La Mun a belong to the group Nasca-
urban whereas all other individuals from sites such as Jauranga or Hanaq Pacha
are grouped as Nasca-rural (Table 10.1).
All successfully analysed individuals belong to one of the four Native American
haplogroups A, B, C, and D (see above). The distribution of the mt-haplogroups
for the analysed populations is found in Table 10.2. For both Paracas populations
there are very high frequencies of haplogroup D followed by haplogroup C with a
much lower fequency. This dominancy of D persists into the Nasca time as seen
with the Nasca (Palpa-rural) population (Table 10.2). For the urban Nasca
population, however, D and C were determined with nearly equal frequencies.
Parallel to the decrease of D there is an increase of haplogroup B which emerges
first in the Palpa area with the Nasca period. This trend continues with
the transition to the Middle Horizon (cf. Table 10.2). The frequency distributions
of the Palpa populations differ significantly from the highland population of
Pacapaccari. Here B is definitely the dominating group and C the only other
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detected (Table 10.2). The frequencies of haplogoup D of all pre-Colombian coast
populations analysed in the context of this study are much higher than in the recent
indigenous Peruvian populations and those of the other northern and southern
central Andean regions (Fig. 10.1).
The HVR I sequence data from the 105 successfully typed individuals could
be assigned to 57 mitochondrial haplotypes of which 32 were single-haplotypes.
Twenty-five haplotypes could be detected in more than one individual. Four ofthem all distinct haplotypes different from the founder types appear syn-
chronous in populations from different archaeological sites, cf. one in the
Jauranga (ParacasPalpa) and the ParacasPeninsula population. Ten haplo-
types persist over more than one time period and appear in different popula-
tions from the Palpa sites (cf. Fehren-Schmitz 2008). All analysed populations
have a high degree of genetic diversity as shown, for example, in the mitochon-
drial Haplotype-Diversity (Hd, Table 10.2). Even though there is a diachronic
and group specific change in the haplogroup frequencies, there is no increase of
overall mitochondrial genetic variability. Other conducted population statisticanalyses (not shown here) verify this conclusion and also that the high frequen-
cies of group D cannot be explained in terms of genetic isolation.
Conducted genetic distance calculations based on the HVR I sequence data
support the considerations derived from the haplogroup data. Very low dis-
tances can be determined between both Paracas period populations and the
rural Nasca group. These three populations cluster in a genetic distance-based
neighbour joining (NJ) tree (Fig. 10.4). The urban Nasca and Middle Horizon
populations exhibit a higher distance to the other three pre-Columbian coast
populations but still cluster within the same branch of the tree whereas therecent indigenous populations of Peru (data: Fuselli et al. 2003; Lewis et al.
2005) and the pre-Columbian Andean highland site of Pacapaccari form a
distinct branch of the tree (Fig. 10.4).
Table 10.2 Mitochondrial haplogroup frequencies and haplotype diversity (HD) for the
Analysed pre-columbian populations
Haplogroup Frequency
Group / Population na Hb A B C D Hdc
Paracas (Peninsula) 10 (6) 5 0,00 0,00 0,30 0,70 0,93Paracas (Palpa) 28 (25) 15 0,07 0,00 0,14 0,79 0,95
NascaRural (Palpa) 37 (30) 26 0,02 0,11 0,22 0,65 0,98
NascaUrban (Palpa) 28 (25) 17 0,00 0,18 0,43 0,39 0,97
Middle Horizon (Palpa) 11 (6) 6 0,00 0,27 0,36 0,36 1,00
Pacapaccari (Highlands) 16 (12) 6 0,00 0,69 0,31 0,00 0,86
a n = Number of individuals with successful haplogroup determination; the number of
individuals with sucessfully determined mt-haplotypes follows in brackets.b H = Number of determined different haplotypes in the population.c Hd = Haplotype diversity (Nei 1987). The value relates to the HVR I sequence data not to
the haplogroup data.
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10.3.2 Ancient DNA Data Translated to the Population History
of South Peru
Combined with knowledge of the cultural and ecological history the population
genetic data can be translated to reconstruct the population dynamic processesof the Palpa region for the investigated timeframe. The genetic similarity of the
Paracas populations from the Palpa area and the peninsula, and also the low
genetic distance between both allows the conclusion that the Paracas culture of
the southern Peruvian coast formed a uniform population. The results also
show that there is a high gene flow, thus migration frequency, within the
distribution area of the Paracas culture but no significant genetic exchange
with the surrounding populations, for example, from the Andean highlands.
Distance calculations and distribution patterns also show that there is a con-
stant population in the Palpa area persisting into the Nasca period. Thesefindings combined with archaeological evidence such as parallels in ornaments
and the existence of early geoglyphs (Reindel and Gruen 2006) suggest that the
Nasca culture of this area evolved from the bearers of the Paracas culture.
Even though the urban and rural Nasca populations exhibit a degree of
genetic distance there is no evidence that this results from foreign influences, as
it would be expected with an elite dominance migration scenario. This assump-
tion is supported by the fact that individuals from the elite burials of La Mun a
share mt-haplotypes with the rural populations. The emergence of haplogroup
B and the differences between the rural and urban populations suggest thatthere is a higher amount of genetic exchange with populations from outside the
investigated coast area, maybe the highlands. This might be a result of the
increase of socioeconomic complexity in the Nasca period which concurrently
Fig. 10.4 NJ-Tree based on the pairwise FST-distances of the analysed pre-Columbian popu-lations (circles) and four recent Native American populations (triangles) from Peru. The
calculations are based on HVR I data. The tree is drawn to scale, with branch lengths in the
same units as those of the evolutionary distances used to infer the phylogenetic tree
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would have caused an increase of the migrational pull-factor of this area.
A grade of social complexity as is reached in the Nasca culture requires craft
and administration specialists (Service 1962). The fact that the genetic popula-
tion structure changes slightly in the Nasca period, and the urban Nasca
population differs from the rural can be best explained by the immigration offoreign specialists into the urban settlements. At the same time these results
verify the urban, respectively, central character of this settlements.
There are no significant genetic changes from the Nasca period to the Middle
Horizon and therewith no evidence for allochthonous contributions to the
Palpa gene pool. Invasion or colonisation scenarios can be rejected as a cause
for the demise of the Nasca culture in this area. The decrease of population
density in the Late Nasca period and the Middle Horizon contrasted with the
constantly high mt-haplotype diversity fits best with scenarios suggesting that
the main settlement area of the people shifts eastwards into the Andean valleysas a consequence of climatic aggravations (Eitel and Ma chtle 2006).
The pre-Columbian populations of the southern Peruvian coast significantly
differ from the recent Peruvian and ancient highland populations although they
are very similar to the recent Native American populations of Middle and South
Chile (cf. Fig. 10.1; Fehren-Schmitz 2008). Mitochondrial distribution patterns
of todays coastal Peru therefore have to be a result of cultural and political
processes succeeding the time span investigated in this study. The high fre-
quency of haplogroup B in recent indigenous Peruvian populations suggests
that the observed genetic changes are best explained by the expansions of thevast-reaching highland empires, especially the Inca. This assumption is sup-
ported by the affinity of the recent Chilean populations to the pre-Columbian
Peruvian coastal populations. The maximum southward geographic extension
of the Inca empire is congruent with the recent border between populations
exhibiting mitochondrial distribution patterns similar to recent Peruvian popu-
lations and Chilean populations that exhibit the ancient coastal patterns
(Fig. 10.1).
10.4 Future Prospects
The conducted investigations and conclusions show that the use of the archive
ancient DNA allows insights into prehistoric population dynamics that could
not be achieved by the analysis of archaeological sources or the use of modern
DNA alone. Although it was possible to gain novel information about pre-
Columbian colonisation and migration processes in western Southern America,
especially the southern Peruvian coastal regions, there is still no information
about equal processes in the Andean highlands. The only available highland
population datasets (this study; Shinoda et al. 2006) date into the Middle
Horizon or the Inca period. To reveal the colonisation and migration processes
that took place in this second major cultural area of western South America,
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studies have to be conducted involving populations dating into the earlier time
periods especially those analysed in the present studies.
Furthermore it should be investigated how far the genetic distribution pat-
terns of the populations that settled in the Andean highlands were also affected
by terms of selective forces. It is imaginable that the harsh environmentalconditions physiological stressors such as hypoxia (Moran 2000) of the
highlands and therewith the necessary adaptive reactions also had influence on
the genetic structures of the populations (Fehren-Schmitz 2008). To answer
these questions new genetic markers have to be explored and analysis systems
suitable for aDNA analysis have to be developed. As mentioned above, knowl-
edge about the colonisation history of South America is still not satisfying. The
presented studies show that one method of resolution for this could be the
genetic analysis of more pre-Columbian populations. The analysis of recent
native South American populations alone will not solve the problem.
172 L. Fehren-Schmitz et al.