Ricerc@Sapienza

The male-specific northern African genetic pool is characterised by a high frequency
of the E-M81 haplogroup, which expanded in very recent times (2-3 kiloyears ago).
As a consequence of their recent coalescence, E-M81 chromosomes often cannot be
completely distinguished on the basis of their Y-STR profiles, unless rapidly-mutating
Y-STRs (RM Y-STRs) are analysed. In this study, we used the Yfiler® Plus kit, which includes
7 RM Y-STRs, to analyse 477 unrelated males coming from 11 northern African populations
sampled from Morocco, Algeria, Libya and Egypt. The Y chromosomes were assigned
to monophyletic lineages after the analysis of 72 stable biallelic polymorphisms and, as
expected, we found a high proportion of E-M81 subjects (about 46%), with frequencies
decreasing from west to east. We found low intra-population diversity indexes, in particular
in the populations that experienced long-term isolation. The AMOVA analysis showed
significant differences between the countries and between most of the 11 populations, with
a rough differentiation between northwestern Africa and northeastern Africa, where the
egyptians Berbers from Siwa represented an outlier population. The comparison between
the Yfiler® and the Yfiler® Plus network of the E-M81 Y chromosomes confirmed the high
power of discrimination of the latter kit, thanks to higher variability of the RM Y-STRs: indeed,
the number of chromosomes sharing the same haplotype was drastically reduced from 201
to 81 and limited, in the latter case, to subjects from the same population.