Mapping studies of the distal imprinting region of mouse Chromosome 2

Abstract

SummaryThe known limits of the distal imprinting region of mouse Chromosome (Chr) 2 are defined by the breakpoints of the translocations T(2;8)2Wa, (T2Wa), and T(2;16)28H, (T28H), in distal H3, and proximal H4 respectively. We have shown that T2Wa and T(2;4)1Go, (T1Go), which has a breakpoint in central H3 map close toa, non-agouti.Ada, adenosine deaminase, lies very near the proximal boundary andRa, ragged, maps very close to the distal boundary, and is less than 0-2 cM from wasted,wst. From the current dataAdacan be taken as the proximal, andRaas the distal gene marker of the imprinting region on the linkage map. From consensus maps twenty three other markers, including fourteen genes, lie betweenAdaandRa, some of which may be useful in investigations of imprinting. Of the markers included in the study reported here, four,Ada,ls, lethal spotting,Raandwstlie or probably lie within the region but none display any evidence of imprinting. We suggest that recombination frequency is elevated in distal Chr 2, because in none of the crosses could the most closely linked marker be ordered in relation to the translocation breakpoint due to the high frequency of double crossovers.