Unselfish meiotic drive maintains heterozygosity in a parthenogenetic ant.
Unselfish meiotic drive maintains heterozygosity in a parthenogenetic ant.
复制标题
无私的减数分裂驱动力维持孤雌蚂蚁的杂合性。
DOI：
10.1101/2024.02.09.579553
复制
发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Kronauer,DanielJC
中科院分区：
文献类型：
--
作者：
Lacy,KipD;Hart,Taylor;Kronauer,DanielJC
根据孟德尔第二定律，染色体在减数分裂中是随机分离的。非随机分离主要是由于雌性的自私减数分裂驱动，在这种情况下，特定的等位基因偏向于将自己的基因传递到卵母细胞1,2。在这里，我们报告了一个罕见的无私减数分裂驱动的例子，交叉遗传在无性系突袭蚁，Ooceraea biroi。该物种通过同一减数分裂的两个单倍体核融合产生孤雌繁殖的二倍体后代。如果交叉重组之后是随机的（孟德尔式）染色体分离，那么由于杂合性的丧失，这一过程会导致快速的基因型退化4,5。然而，通过比较母亲和女儿的全基因组，我们发现杂合性的丧失是极其罕见的，这提高了在O. biroi减数分裂中杂交不频繁或不存在的可能性。利用细胞学和全基因组测序的结合，我们表明交叉重组实际上是常见的，但由于交叉产物忠实地共同遗传，因此避免了杂合性的损失。这是由于程序违反了孟德尔的隔离定律，这样交叉产品就会隔离在一起，而不是随机分离。这一发现突出了细胞“记忆”交叉的一个极端例子，这可能是染色体分离的一个常见但神秘的特征。
According to Mendel’s second law, chromosomes segregate randomly in meiosis. Nonrandom segregation is primarily known for cases of selfish meiotic drive in females, in which particular alleles bias their own transmission into the oocyte1,2. Here, we report a rare example of unselfish meiotic drive for crossover inheritance in the clonal raider ant, Ooceraea biroi. This species produces diploid offspring parthenogenetically via fusion of two haploid nuclei from the same meiosis3. This process should cause rapid genotypic degeneration due to loss of heterozygosity, which results if crossover recombination is followed by random (Mendelian) segregation of chromosomes4,5. However, by comparing whole genomes of mothers and daughters, we show that loss of heterozygosity is exceedingly rare, raising the possibility that crossovers are infrequent or absent in O. biroi meiosis. Using a combination of cytology and whole genome sequencing, we show that crossover recombination is, in fact, common, but that loss of heterozygosity is avoided because crossover products are faithfully co-inherited. This results from a programmed violation of Mendel’s law of segregation, such that crossover products segregate together rather than randomly. This discovery highlights an extreme example of cellular “memory” of crossovers, which could be a common yet cryptic feature of chromosomal segregation.