International Mammalian Genome Society

The 15th International Mouse Genome Conference (2001)

Table of Contents * Complex Genetics * Developmental Genetics * Gene Annotation * Gene Discovery * Genome Sequencing * Functional Genomics * Mutagenesis * Presentations * Verne Chapman Memorial Lecture

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POSTER 60 - THE HARWELL MOUSE IMPRINTING MAP

Colin V Beechey
Mammalian Genetics Unit
Harwell
Didcot
Oxon OX11 0RD UK

Co-Author:  Cattanach BM
Institution:   Mammalian Genetics Unit, Harwell

An up-to–date version of the Harwell Mouse Imprinting Map with associated data and references is presented. The map illustrates those regions of the genome subject to imprinting as defined by the occurrence of anomalous phenotypes with uniparental duplication.  These imprinting regions, and the chromosome anomalies defining them, are illustrated on both the genetic and G-banded map with all currently known imprinted genes. Human homologous regions are also shown. Almost all identified imprinted genes map to these imprinting regions although a small number do not.  One such gene is Rasgrf1, located on distal Chr 9.  Maternal transmission of a Rasgrf1 knockout leads to postnatal growth retardation.  Re-investigation of distal Chr 9, using several different translocations to generate uniparental duplications, has now identified a similar postnatal growth retardation with maternal duplication.  This effect was previously attributed to distal Chr 17 but these new findings mean that the conflict in the data no longer exists.  Another investigation has focused on proximal Chr 2, which has shown variable evidence of imprinting. New studies have firmly established that a region close to the centromere is subject to imprinting with effects on foetal viability, growth and placental size, although to date no imprinted genes have been identified here. The imprinting regions shown on the Harwell Map now define the sites of all but 3 identified imprinted genes, Htr2a (Chr14), Ins1 (Chr 19) and Zac1 (Chr10). This inconsistency could be due to subtle or variable imprinting phenotypes associated with uniparental duplication of these chromosome regions.