A revised map of chromosome 1

Abstract

The genetic map of chromosome 1 reported by Keats, Morton & Rao (1981) has been updated using recent recombination data and regional assignments from the Galton Laboratory (King, 1982a) and from the current literature. A maximum likelihood mapping technique using pairwise recombination data without a chiasma map was developed, based on the principles of Rao et al. (1979) and Keats et al. (1981). The development of this new method was found to be necessary when inconsistencies were encountered using a method which combines recombination data and physical data through the chiasma map. These inconsistencies could be due to appreciable chiasma movement, incorrect physical assignments or technical and biological variation in lod scores.

Report of the committee on the genetic constitution of chromosomes 1 and 2

“…The same data base, together with small amounts of more recent data, was used by Sherman et al to compute male and female genetic maps (Sherman et al 1984). The order of the two maps derived differs slightly, that of Wedd placing PGD distal to EN01, UMPK distal to SC and CAE and FY on lp rather than lq.…”

“…It was also partly the mapping of PGM1 outside its SRO which induced Sherman et al (1984) to abandon the chiasma map and rely only on recombination data. An alternative explanation as suggested by Darby et al (1985a) would be a region of high frequency of recombination within lp22.1 and between PGM1 and NGFB.…”

“…Fig. 2 represents a recalculation of the best male genetic map using these lod scores and the method of Sherman et al (1984). The gene order allowed was constrained by firm physical regional assignments, but information from three point data was not included.…”

A genetic map of chromosome 19 based on family linkage data

“…The method for obtaining the best order and map distances based on two-point lod tables using the programme MAP83 has been fully described previously ;Keats, Morton & Rao, 1981 ;Sherman et al 1984). Briefly MAP83 analyses lod score tables of all pairwise combinations of markers, separated by sex.…”

Report of the committee on linkage data and gene order

“…BJBK held that pairwise lod tables are the only feasible way of summarizing the data such that results from many studies can be combined. These data may then be used to estimate most likely maps with a program such as MAP83 Keats et al 1981;Sherman et al 1984). While it is true that some information about order is lost when pairwise data are analyzed, computing time is short and the maps derived by this method are so far not inconsistent with those derived from the raw data.…”