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Presenting Author(s) Frantisek Liska
Abstract Title Systematic screening of candidate genes for the rat hypodactylous mutation.
Full author List Liska F, Goesele C, Kren V, Chylikova B, Jirsova Z, Hubner N, Krenova D
Text of abstract

Rat hypodactyly (Hd) is an autosomal recessive mutation leading in homozygous condition (Hd/Hd) to reductive changes of digital arch of all feet in both sexes. Fingers and toes II and III are missing or distally truncated. Homozygous males are infertile and possess abnormal spermatogenesis resulting in oligo- terato- asthenospermia with marked tail fragility.

Using linkage mapping in both backcross (n=320) and intercross (n=447) segregating populations, we narrowed Hd position to a 0.17 cM nonrecombinant interval on rat chromosome 10, flanked by markers D10Mit8 and D10Cub7. Physical map of the region was constructed using BAC library RPCI-32. 6 BAC clones form a minimal tiling path through the contig consisting of 19 overlapping clones. According to the rat genome version 3.1, the interval between D10Mit8 and D10Cub7 spans 694 kb and contains 30 genes and gene predictions, all conserved among mammalian genomes (RNO10, MMU11, HSA17p13). 21 genes were expressed in adult testes when assayed by RT-PCR.

None of the testis-expressed genes was, according to database and literature data, connected with limb abnormalities or male infertility. Dissection of Hd can therefore point to a novel facet of limb patterning as well as development of spermatozoa. Up to now, the protein-coding sequences (CDS) of 10 testis-expressed genes were sequenced (Alox12b, Mum2, Efnb3, MGC28622, Tp53, Atp1b2, Shbg, Ssat2, Fxr2 and Sox15). Although several polymorphic nucleotides were observed, the involvement of these in limb malformation was excluded by the presence of the same variant in one of the control strains. Sequencing of CDS of remaining 11 candidate genes is underway. If the pathogenesis of Hd could not be fully elucidated by candidate gene approach, we will consider regulatory mutations.

Supported by grant GACR 301/02/0464 of Grant Agency of the Czech Republic

Which session is your work most relevant to: Limb patterning