A torrid zone on mouse chromosome 1 containing a cluster of recombinational hotspots.
Within the 2.38-Mb Ath1 region of mouse chromosome 1, 42 of 45 genetic crossovers from crosses between C57BL/6J (B6) and either C3H/HeJ (H) or Mus spretus (SPRET) occurred in four zones (A-D); zone A, 100 kb long, contained a cluster of at least four recombination hotspots. F1 sperm assays indicate that within this "torrid zone" the most active hotspot (A3) can initiate recombination on H and SPRET but not B6 chromosomes. The A3 DNA sequence contains a (G/C)TTT repeat, long stretches of A or T, and a cyclic variation in AT content. Recombination was drastically reduced in a cross between B6 and a B6.SPRET Ath1 congenic strain, but was unaffected in a B6 x B6.H Ath1 congenic cross. Similar nonrandom clustering of hotspots has been observed in yeast and the major histocompatibility complexes of human and mouse. To the extent that torrid zones are a general feature of mammalian genomes, they have considerable implications for genetic mapping strategies in both human populations and mouse crosses.
The Jackson Laboratory, Bar Harbor, Maine 04609-1500, USA.
Peter M
PM
Kelmenson
Petko
P
Petkov
Xiaosong
X
Wang
David C
DC
Higgins
Beverly J
BJ
Paigen
Kenneth
K
Paigen
D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D002875:Chromosomes; D003433:Crosses, Genetic; D008297:Male; D051379:Mice; D020297:Mice, Congenic; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013094:Spermatozoa / Q000166:cytology