ZOO-FISH analysis in insectivores: “Evolution extols the virtue of the status quo”

Abstract

In evolutionary terms, insectivores are thought to be close to primates. Through ZOO-FISH analysis using human chromosome-specific painting probes, the syntenic relationship between the human and common shrew, Sorex araneus, karyotypes was studied. The human karyotype was found to be conserved in the shrew, with 32 autosomal segments of common synteny. Special arrangements, already known from similar studies on other species, were noted: fusions of HSA 16 and 19, HSA 3 and 21, and HSA 14 and 15. Only 10 breaks are necessary to transform the human karyotype into the karyotype of the common shrew. Together with known ZOO-FISH data from species belonging to other orders, this puts the human karyotype arrangement near the basis of all mammalian karyotypes. Human chromosome 2 was found to be conserved in its entirety as a single chromosome arm in the shrew. Evidence is presented that the same fusion of two original chromosomal segments formed the shrew chromosome ortholog of HSA 2 as the fusion that occurred during primate evolution to form human chromosome 2. This is a remarkable example of chromosomal coevolution.

Standard DAPI karyotype of the common shrew Sorex araneus L. (Soricidae, Eulipotyphla)

“…The Novosibirsk chromosome race of common shrew, which was one of the first races described (Král & Radjabli, 1974), recently has become a model for comparative gene mapping, with extensive use of FISH with specific DNA probes (Dixkens et al, 1998;Zhdanova et al, 2005). The application of G-banding to FISH studies is time-consuming and is often unreliable.…”

Phylogenetic Origin of Human Chromosomes 7, 16, and 19 and their Homologs in Placental Mammals

“…They also confirmed the proposed analogies between man and great apes (Dutrillaux 1975;, man and macaques (Muleris et al 1984;Wienberg et al 1992), and man and lemurs (Apiou et al 1996;Mü ller et al 1997). These improvements make it now possible to accurately compare man and nonprimate mammals (Hayes 1995;Rettenberger et al 1995;Frönicke et al 1996Frönicke et al , 1997Raudsepp et al 1996;Hameister et al 1997;Wienberg et al 1997;Bielec et al 1998;Dixkens et al 1998;Nash et al 1998;Volleth et al 1999) and reconstruct the origin of human and other primate chromosomes from their common eutherian ancestors.…”

Mapping of five genes from human chromosome 17 to chromosome hn of the common shrew Sorex araneus

“…In dogs this group is presented as two blocks of conserved synteny (Werner et al 1997). The localization of two genetic markers and zoo-FISH analysis suggested the conservation of the human chromosome 17 gene association to the common shrew (Sorex araneus) chromosome hn, precisely to its /i-arm (Pack et al 1995, Malchenko et al 1996, Dixkens et al 1998. In this work we apply a zoo-PCR approach to map human chromosome 17 genes in S. araneus.…”