Figure 3.—

Mapping of exchange points among complex CO products. One hundred twenty-two COs and 308 COs were mapped in wt and Mlh3^−/− (respectively) from genomic DNA of day 17 and day 19 pp testes. They were obtained as 4-kb molecules amplified with primers at positions 402 and 4315. The hot spot, identified by a shaded bar, is located between the TaqI and Eco57I sites and centered in the BsrFI–StyI region. Red and black lines represent B6 and R209 haplotypes, respectively. Those molecules with unusual positions of exchange points, i.e., more than one exchange point or an exchange point outside the TaqI–Eco57I interval, were sequenced and divided into three categories: molecules with a distal exchange point, multiple exchanges, and mixed strands.