Ricerc@Sapienza

One of the most striking structural features of the male specific region of the human Y
chromosome (MSY) is the presence, within the ampliconic sequences, of eight massive
palindromes (P1-P8). Each palindrome is composed of two large inverted repeats (arms)
separated by a small “spacer” sequence at the centre. These elements, ranging from 30 kb
to 2.9 Mb, contain many testis-specific genes and typically exhibit > 99.9% intra-palindromic

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 and 20 standard Y-STR, to analyse 477 unrelated males coming from 11 northern African populations sampled from Morocco, Algeria, Libya and Egypt.

The Talpidae family has a highly stable karyotype. Most of the chromosome studies in this mammal group, however, employed classical cytogenetic techniques. Molecular cytogenetic analyses are still scarce and, for example, no repeated DNA sequences have been described to date. In this work, we used sequence analysis, chromosomal mapping of a LINE1 retroelement sequence, as well as chromosome painting with a whole Y chromosome probe of T. occidentalis to compare the karyotypes of 3 species of the genus Talpa (T. occidentalis, T. romana, and T. aquitania).

The male-specific region of the human Y chromosome (MSY) is characterized by the lack of meiotic recombination and it has long been considered an evolutionary independent region of the human genome. In recent years, however, the idea that human MSY did not have an independent evolutionary history begun to emerge with the discovery that inter-chromosomal gene conversion (ICGC) can modulate the genetic diversity of some portions of this genomic region.

The presence of large and near-identical inverted repeat sequences (called palindromes) is a common feature of the constitutively haploid sex chromosomes of different species. Despite the fact palindromes originated in a non-recombining context, they have evolved a strong recombinational activity in the form of abundant arm-to-arm gene conversion. Their independent appearance in different species suggests they can have a profound biological significance that has yet to be fully clarified.