Comparative genome mapping in mammals: the shrew map

Comparative mapping has shown that the genome evolution of eutherian mammal s mostly involves movement of large blocks of genes. Zoo-FISH analysis has revealed that 23 to 56 blocks of human chromosome material are conserved in different mammalian genomes. Several syntenic groups of genes are found in most mammalian orders: some involve complete or partial human chromosomes and others involve segments that are found in a fused state in most mammals but separated in the human genome. It can be hypothesized that these conse rved syntenic groups were present in the ancestral genome of all eutherian mammals. There is a need to obtain data from as wide a taxonomic spread of mammals as possible to further elucidate this ancestral genome. We have ini tiated studies on the order Insectivora and have located 45 genetic markers in the common shrew Sorer: araneus Linnaeus, 1758. Zoo-FISH analysis shows conservation of human chromosome material in shrews in 32 blocks and that the shrew genome shares many of the conserved chromosome segments found in other mammalian orders.