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VOL. 72 (1), 37-47, 2006 MITOCHONDRIAL LINEAGES DISTRIBUTION IN THE SPANISH...

RESULTS

The analysis of 686 Spaniard individuals from North and center
of Spain gave us a picture of the haplogroup frequencies in the
Spanish population (Table 2). Then, we compared our results with
those from a collection of 718 Spaniard samples from the literature
coming from the whole country (Table 2). The individual haplogroup
frequencies were very similar, although we found significant
differences (? = 29.8, df = 9, P < 0.001). These differences were due
to an excess of HV* [P (post-hoc cell contribution-phcc) < 0.001] and
a defect of W [P (phcc) = 0.009] individuals in our samples versus
the other studies {HV*, [P (phcc ) < 0.001]; W, [P (phcc) = 0.012]}.
However, there was no difference in the major haplogroups. As we
were interested in the haplogroup distribution in the whole country
because epidemiologic studies require large populations and because
the differences were only found in minor haplogroups, we decided
to combine all the individuals in a big Spanish sample (1404
individuals).

Next, we compared the whole Spanish sample with a collection
of 2648 European individuals from the literature (Table 2). We found
significant differences in the haplogroup distribution (? = 136.0, df
= 9, P < 0.001). H, V and HV* were overrepresented in the Spanish
population but T, I, and O lineages were underrepresented [P (phcc)
= 0.009, for all of them]. The opposite tendency was found in the
European samples [P (phcc) = 0.001, for H, HV*, I and O].

Mitochondrial haplogroup U is an ancient cluster widely
distributed in Western Eurasian and very well genetically defined.
Therefore, we subdivided our 155 U samples in subhaplogroups and
compared them to 1802 U European (6) and 455 Italian individuals
(24) (Table 3). Despite some classification problems, we were able to
confirm the previously observed tendency in the subhaplogroups U
distribution. Those subhaplogroups defined by changes in very well
evolutionary conserved positions in the cytochrome b were
overrepresented in northern latitudes, the rest were prevalent in
southern latitudes (Table 3). An exception was mitochondrial
subhaplogroup K. Its prevalence was clearly higher in the South in
both Spanish and Italian populations.

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