Mesolithic/Neolithic Boundary (1) From Whence They Came.

To begin the discussion of the Mesolithic/Neolithic Boundary
make sense of the genetics we need to establish some big
or generalized events. The biggest single event that has occurred
in human history since humans left Africa is the Last Glacial
Maximum, by 25kya things were really bad for most peoples living
outside of the tropics. People living in the tropics, places
like indonesia were at the peak of land mass, and of course
sea routes were available for hopping that where at their peak.
If the LGM were to occur today in europe you would see a
massive flux people and large numbers of people would perish
as the available land for agriculture would drop. Places like
India, africa, australia, indonesia, central america, south
america would surpass the 'west' in production. Land animals
in some areas would drop and new species like reindeer, furry
bison and bison would prevail, if we had them, wooly mammoth.
Episodic period of really bad weather, as the report of britian
would occur and wipe out most terrestrial resources. There might
not be enough animals in one place at any one time for people to
exist in sedentary lifestyles.
The whole world does not concern this particular argument only
what we call the temperate western part of asia to this argument
we should attach the northern part of africa. Why? Because we can
use the LGM as sort of a focal point for explaining future migrations.
Condensing populations to a fraction of their original size helps
to create uniqueness at the genetic level, and this can be used
as a probe to define where people come and go.

The Iberian Refuge.
Let me start from the west, what do we know. It seems that we
know there was an refuge in the LGM known as iberia. Iberia itself
is enigmatic not only because ecological studies show that many
small varmit species took haven during the LGM, but also its fairly
close to africa and humans have had a tendancy to cross from africa
into iberia, more so than going the opposite direction, at least
over the long haul. At the peak of the LGM iberia has humans, it
is forested but who living in africa really wants to migrate into
iberia. The atlantic forces are at their lowest, cold winds drive off
glaciers the only protection being a modest mountain range. Flow in
and out of the mediterranean has been reduced. But on the other hand
the iberian oasis from the LGM is a potential launching board for
migrations at the end of the younger dryas.
I can say this, there is no particular group in iberias NE quadrant
that looks like it colonized europe after the LGM. Even though the oasis
extended into southern france there also appears to be no people that
launched to recolonize the north. OTOH do we assume that the current
inhabitants were always in key positions to launch such adventures.
Well, this particular argument needs to be looked at carefully,
because depending how we create the argument the result will differ.
Two groups in Iberia pique the interest of molecular anthroplogist, 1
is the pas, who have these odd, almost primative collection of northern
haplotypes, and the basque who have this strong affinity with the west.
If one takes a look at iberia and looks at the arratia region of spain,
directly north of arratia is the bay of biscayne. The moutains of the
region push up against the northern coast of spain and even the midst of
the LGM the current coast drops into the ocean rapidly. Some details
will be given later but there was a strong mesolithic culture that
was preserved in the region, largely because of its 'neolithic'
unsuitability (Neolithic requiring agriculture). As one can imagine
the appearance of the Mesolithic is accompanied with littoral
exploitation but also many transitional animals for pastoral life
style, fairly common now amoung the basque. From san sebastion on
can trek up the french coast in what is now the bay of biscayne,
however one stoppin point is reache at the ardone river, which
presents a submarine canyon in which atlantic waters would have come
to the coast, potentially glacial masses from time to time carved
out this canyone, beyond this opens up the cold plains to the north and
northwest all now submerged, access to even southern Ireland.
During the late pliestocene period food supplies to the east would have
been restricted to durable cold climate animals, types of animals that
might be hunted when times were really tough, there may have been an oasis
off the french coast, its is unclear, by the time on reaches the trough of
the english channel we can assume humans would be at the extreme upper
limit of cold tolerance, potentialy during warm periods they migrated up
and down this coast, during cold periods they retreated to the southern
extent. The Mesolithic middens suggest that coastal productivity in
northern spain was not good, densities appear to be lower than other sites,
and the use of land animal food sources appears to have been required.
When we get into the genetic argument this opinion should have some value.
Oddly however badger and other animals found the region about San Sebastion
a favored [Mammal Review 34 (2004) 249,284] plenigalical habitat during the
LGM, Western france should be appart of that range, and numerous genera
are found in the Late glacial period. So that with regard to france, we
have to consider the probability that the iberian glacial refuge extended
further along the coast northward; however, how far northward one cannot
say, if I were to draw a line on the map I would project out Loire river
tangent to the coast. Beyond this the means of subsistance would need to be
specialized toward persistent fauna (marine or terrestrial), the
availability of wood is questionable, there are places along the submarine
relief that could have provided the bounty of fish and sea life capable of
supporting very specialized humans. The principle issue however is that
would have to have been specialized to a degree and technologies that would
have been competitive with much later societies. It is a stretch.
There is another sub-refuge that is apparent in the animal studies,
a number of pleniglacial and late glacial remains have been found to the
west of the french alps. These are worth mentioning now because they may
play a role in understanding the Mesolithic/Neolithic transition. The
animal studies, if I am interpreting them correctly suggest connectivity
with iberia and not italy at the pleniglacial period.
A final thought on Iberia. Archaeological studies tend to favor
finds of sedentary peoples, lets face it, if you are going to study
a site you would tend to put an effort into a site with many inhumations,
many middens, and depths of culture. While the HLA can attest to nodality
in portugal representing pre-neolithic inhabitants and of course we have
the pas and Basque, there are nodes in the interior of spain, and probably
more than I can safely say are known thus the interior of iberia may have
had completely mobile H/G with no sedentary impulses. The other problem
for france, there are many undeveloped/unpublished sites, this has been
admitted several times in the literature, I will take no more flak for
stating this as it is a fact. Even if this were not the case, frances
western coast at LGM sea levels is quite distal from the current coast,
and the only real way I know that we might detect arboreal patterns is
by coring the sea floor for woody materials and C14 dating these materials.
There is no hope of finding pre-mesolithic artefacts except by pure luck.
We can assume that the gulf of leon was active, and its inhabitants
should be a matter of our concern.
To call iberia a refuge is a little bit euphemistic, there is no great
evidence to suggest people returned to iberia at the LGM, or that they
prevelantly left iberia. Iberia is more or less a corridor of travel from
africa in which people made unknown lengths of pitstops before moving
north.

The 'Austro-Romanian Oasis' (Carpathian/Moldovan glacial refuge).
From my first analysis of the HLA years back it was quite noticable that
austrians, despite cultural similarities with swiss and germans had notable
haplotypes from the east, some of these were nodal to australia. I proposed
that there had to be a romanian oasis, a place along the black sea where
the earliest austrians returned and settled. The animal studies suggest
this was NW of the black sea and extended into northern Romania. I have no
idea why this refuge existed but it is parsimonious with other HLA
information also for the northern and northeastern part of europe. The
effects in the subsequent development of eastern europe is something I have
not particularly focused on principally because our concern has been on the
developement in the habitable lands between the eastern germany and
northern spain. I fear also that the region has suffered so many migrations
that interpretation of the results is not going to be beneficial or
reliable.

The north africa refuge.
Not neccesarily a refuge from glaciers, the LGM however had an
aridization effect on eastern africa, pushing the coastal grasslands close
to the mediterranean, there may have been grassland expansions in the north
western regions as some studies suggest, as cold air driven off of europe
passed over the western mediterranean and picked up moisture. The timing of
migrations to and from sardinia, iberia and italy are not clear, but
certainly before the LGM and after the LGM migrations did occur. The africa
wild ox [Bos primagenius mauritanicus] perdecessor to the african cattle
may have spent the LGM in this refuge, for that reason it is worthy to
mention. During the late pleistocene grasslands in africa coastal regions
probably came and went with some frequency, acting as a pump into europe.
Explanations as to why these are not evidence before 33 kya when migrations
to austronesia are evidence before 65 kya are evident is something worth
exploring, but not here. It is probable that the first africans appeared in
NW iberia about the time when the first H/G arrived from the east into
france ~35 kya. The genetic data suggest connectivity with western africa,
but the timing bases on LD appears to be quite late, less than 10000 years
ago.

The Greco/Balkans refuge.
The animal studies suggest that there was a boreal corridor that extended
from greece and the SW black sea up to the SE alpine region. HLA studies
corroborate that humans probably survived in this region as 1 or 2 groups.
The balkans are also notable because Bos primagenius primagenius, the
ancestor to bos taurus appears to have been derived at least in part from
this region, typically during the mesolithic and earlier periods were Bpp
is found also Bpp bones are found in anthropogenic middens, its a
reasonably good sign that populations are doing well. So a local PMRCA for
Bpp is a good sign for human existence.

The Italian refuge.
To say that the Italian refuge existed and finding corroborating evidence
of it in the human studies has been perplexing. The basic problem with the
Italian refuge from a human point of view is that it is troubled by the
same problems as the french-german comparisons. I don't like being wrong,
but over the last 2 or 3 years study after study showed subsequent linkage
of distal indigeonous peoples to this particular population. In addition a
number of instances of bimodality between alleles that should have left
africa before the LGM show up being shared between the balkans and italy,
and no modern migration from africa can explain this, even the holocene
migration from the nile valley left traces of SSA alleles in the grecan and
black sea population. The migration from africa that produced these
similarities appears to have exited from a north or northeastern corridor
before SSA central african populations had access to the northern regions
(After the eastward directed migrations 10ks years earlier). Some of the
diversity can be explained by recent migrations, but we will find the need
to much of italian diversity as one archaeological argument can potentially
explain the franco-germanic diversity it needs to be something of a
reasonably early existence, IOW prior to the late mesolithic.
There has been alot of flux in and out of italy, I generally do
not like to use such hand waving arguments as explanations, however history
can only define about 4000 years of a required 18000 post-LGM period and
that aint much. I can rearrange the argument and then let the reader
decide what is required. The level of diversity of the italian population
in particular aspects of the HLA that appear to be ancient suggest
no signficant constriction in population size as a result of the LGM.
By significant I mean relative to the NW iberian group, the
austrian/northern european grouping. The basic assumption is that
if Italy was an enclave, then likely the population and number of
autonomous groups in italy was as great as the austrian/iberian refuges
combined. Several possibilities are that it was a collection of both
north african and italian peoples that exchanged gametes over a broader
region, but not to the northwest. The HLA studies suggest that there
was no dominant node within this population, and some of the haplotypes
found are bimodal with extreme regions of east asia.
To state there is a problem with hypothesis creation and testing of
theories regarding this population is to understate the case. The primary
issue regards Africa. It is of general notation that a number of alleles
that are bimodal and form a long corridor across asia and even the western
new world indigenous population are found in Italy and sometimes at peak
values, these alleles are derivatives of african allele types that are
known to have originated in Africa. This is not one expects from influxes
and migrations, its what one expects from source nodes are assymetric
expansions. Theoretically, italy being between western contact and eastern
contact with Africa would be isolated to a greater degree than either end.
And yet the character of the northern near and middle east is more similar
to italy than HLA than to the peoples sitting at close to the Sinai. There
does not appear to be a gradient of genes from the levant to Italy that
explains the often rich African alleles. One possibility is that the
assumption of nodality for Italy as a result of LGM events may be a bad
assumption, a good assumption elsewhere but bad in Italy. During the LGM
sea levels would have reached their lowest, allowing migrations back and
forth to Africa over relatively short distances, possibly even without
watercraft, grasslands on the African side may have drawn H/G into the
region and across into peninsula as grasslands disappeared. Tool
technologies may have been introduced to the region at this time. Given
enough potential micronodes we don't actually need to produce dominant
nodal analysis, as long as we believe that once the corridor close the
italian peninsula was capable of supporting a rather robust population for
a few 1000 years. All of this is speculation.
Cattle appears to be a part of this equation at least the wild oxen were
abundant enough to produce diversity, wild cattle may have traversed
between italy and africa and this may be how they reached africa, although
african diversity suggests at least one other path. Italy is a place were
cattle diversity also peaks in western europe.
Grain production in Italy appears to have a local quality, seeds of many
grasses have been found, and early strains of triticeae were developed in
Italy, as mentioned the Oak specific to Italy is found in switzerland
appear to have taken an eastern and then western route to get there. Some
of the base grasses strain that eventually become wheat are indigenous to
italy, but these genetically are outgroup to the actual grasses, except
possibly on derivative cultivar.

5 refuges of genes have been produced, we can add to that the middle east
(Anatolia and the Levant) From these 5 refuges we need to explain the
settlement of europe in some cogent manner and see if any of these
explanations overlap with the archaeological hypotheses. The basic formula
for the refuge is that during the LGM populations will be compressed,
compression leads to drift and biasing of allele and haplotype frequencies
and creating population character. At least 3 of our refuges show
characters that one expects given the LGM, the other isn't affected
directly by glaciation, and the last one appears not to have undergone
significant population reductions.






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