Data from: Male mouse recombination maps for each autosome identified by chromosome painting

Linkage maps constructed from genetic analysis of gene order and crossover
frequency provide few clues to the basis of the genomewide distribution of
meiotic recombination, such as chromosome structure, that influences
meiotic recombination. To bridge this gap, we have generated the first
cytological recombination map that identifies individual autosomes in the
male mouse. We prepared meiotic chromosome (synaptonemal complex [SC])
spreads from 110 mouse spermatocytes, identified each autosome by
multicolor fluorescence in situ hybridization of chromosome- specific DNA
libraries, and mapped 12,000 sites of recombination along individual
autosomes, using immunolocalization of MLH1, a mismatch repair protein
that marks crossover sites. We show that SC length is strongly correlated
with crossover frequency and distribution. Although the length of most SCs
corresponds to that predicted from their mitotic chromosome length rank,
several SCs are longer or shorter than expected, with corresponding
increases and decreases in MLH1 frequency. Although all bivalents share
certain general recombination features, such as few crossovers near the
centromeres and a high rate of distal recombination, individual bivalents
have unique patterns of crossover distribution along their length. In
addition to SC length, other, as-yet-unidentified, factors influence
crossover distribution leading to hot regions on individual chromosomes,
with recombination frequencies as much as six times higher than average,
as well as cold spots with no recombination. By reprobing the SC spreads
with genetically mapped BACs, we demonstrate a robust strategy for
integrating genetic linkage and physical contig maps with mitotic and
meiotic chromosome structure.

基于基因顺序与交换频率的遗传分析所构建的连锁图谱，难以揭示影响减数分裂重组的核心因素（如染色体结构）与减数分裂重组全基因组分布之间的内在关联机制。为填补这一研究空白，我们首次构建了可识别雄性小鼠个体常染色体的细胞学重组图谱。我们从110个小鼠精母细胞中制备了减数分裂染色体（联会复合体[synaptonemal complex, SC]）铺片，通过染色体特异性DNA文库的多色荧光原位杂交技术识别每一条常染色体，并利用标记交换位点的错配修复蛋白MLH1的免疫定位方法，在单条常染色体上定位了12000个重组位点。研究表明，SC长度与交换频率及分布模式显著相关。尽管大多数SC的长度与其有丝分裂染色体长度等级的预测值相符，但仍有部分SC的长度超出或低于预期，伴随MLH1信号频率出现相应的升高或降低。尽管所有二价体均具备部分通用重组特征，例如着丝粒附近交换事件较少、远端区域重组发生率较高，但单条二价体沿其长度均拥有独特的交换分布模式。除SC长度外，其他尚未明确的因素同样会影响交换分布，进而在个别染色体上形成重组热点区域（其重组频率最高可达平均水平的6倍），同时也存在无任何重组事件的冷点区域。通过使用经遗传定位的细菌人工染色体（Bacterial Artificial Chromosome, BAC）对SC铺片进行再探针杂交，我们证实了一种可将遗传连锁图谱与物理重叠群图谱、有丝分裂及减数分裂染色体结构进行整合的可靠策略。