Multipoint analysis of chromosome 11p markers.

The nature of the problems posed for the l l p segment of the fourth Genetic Analysis Workshop w e r e discussed in some detail i n the summary paper, as w e r e the characteristics of the two data sets available for analysis. W e assume that the reader is familiar w i t h the summary and therefore make no attenpt t o duplicate this information here. Our efforts in the analysis of the workshop data focvsed primarily on three different approaches t o the multipoint napping problem. Specifically, we wanted t o know i f gene order could be determined and a reasonable genetic map be constructed through the use of simple gametic counting procedures. Our second approach w a s t o analyze the data using a model incorporathy a prior distribution of chiasroata t o f i t relative genetic distances t o the obtained gametic frequency counts. This approach is similar t o the method which we described in GAW I11 (Fain and Goldgar, 1985). Use of these methak required that 4 locus phase could be determined either directly f m grandparental genotypes or indirectly from examination of very large sibshi~. Consequently, we concentrated our efforts on the large three generation families contained i n the WAFI data set, and our report w i l l be limited t o the analysis of t h i s data set.