More than a year ago I commented (as much as I could) on the study of Italian haploid genetics by Francesca Brisighelli et al. Sadly the study was published with several major errors in the figures, making it impossible to get anything straight.
I know directly from the lead author that the team has been trying since then to get the paper corrected but this correction was once and again delayed by apparent inefficiency of PLoS ONE's management, much to their frustration. Finally this week the correction has been published and the figures corrected.
So let's give this study another chance:
Francesca Brisighelli et al., Uniparental Markers of Contemporary Italian Population Reveals Details on Its Pre-Roman Heritage. PLoS ONE 2012 (formally corrected in February 2014). Open access → LINK [doi:10.1371/journal.pone.0050794]
Notice please that you have to read the formal correction in order to access the new figures, the wrong ones are still in the paper as such.
The corrected figures are central to the study:
|Figure 1 (corrected). Map showing the location of the samples analyzed in the present study and those collected from the literature (see Table 1).|
Pie charts on the left display the distribution of mtDNA haplogroup frequencies, and those on the right the Y-chromosome haplogroup frequencies.
So now we know that the Northern mtDNA pie was duplicated in the original graph and that Central Italians are outstanding in R0(xH,V), which reaches 14% (probably most HV*), while they have some other peculiarities relative to their neighbors from North and South: some less U and no detected V.
Other variations are more clinal: H decreases from North to South while J and T do the opposite.
|Figure 3 (corrected). Phylogeny of Y-chromosome SNPs and haplogroup frequencies in different Italian populations.|
In the Y-DNA side, the most obvious transition is between the high frequencies of R1b1a2-M269 (R1b3 in the paper) in the North versus much lower frequencies in the South. But also:
- J2 is notorious in the Central region (and also the South) but rare in the North.
- G frequencies in the South are double than those of Center and North.
- The same happens with lesser intensity regarding E1b1b1-M35 (E3b in the study).
- In contrast haplogroup I is most common in the North. However the Sardinian and sub-Pyrenean clade I2a1a-M26 (I1b2 in the paper), which is also the one documented in Chalcolithic Languedoc, is rare in all regions.
The study also deals with several isolated populations:
|Figure 4. Haplogroup frequencies of Ladins, Grecani Salentini and Lucera compared to the rest of the Italian populations analyzed in the present study.|
All them show large frequencies of mtDNA H relative to their regions. The Grecani Salentini do have some extra Y-DNA E1b1b1 (E3b) and J2, what may indeed underline their partial Greek origins. The Ladini show unusually high frequencies of R1b*(xR1b1a2) and K*(xR1a,R1b,L,T,N3), while the Lucerans are outstanding in their percentage of G.
I want to end this entry with a much needed scolding to the staff of PLoS ONE for their totally unacceptable original sloppiness and delay in the correction. And my personal thanks and appreciation to Francesca Brisighelli for her indefatigable persistence and enthusiasm for her work, which is no doubt of great interest.