Laboratory of Animal Resource Development, Faculty of Agriculture, Saga University, 1 Honjo-machi, Saga 840-8502, Japan.
Hum Reprod. 2010 Feb;25(2):457-61. doi: 10.1093/humrep/dep400. Epub 2009 Dec 1.
Females live longer than males in many mammalian species, including humans. It has been observed that women are at an advantage over men with regard to the lifespan; however, the reason for this sex difference in longevity is unclear. Bi-maternal mice (BM), which are produced in a 'sperm-free' manner, could provide an opportunity to analyse the longevity of animals lacking paternal genomes.
We studied the longevity of BM, which were generated using two sets of female genomes--one derived from fully grown oocytes from normal adults and the other from non-growing oocytes from newborn pups. These newborn pups were also genetically manipulated in two regions--the imprinting centres of Igf2-H19 and Dlk1-Gtl2--on chromosomes 7 and 12. We determined lifespan of the control (n = 13) and BM (n = 13). Our results revealed that the bi-maternal genotype clearly shifted the entire survival curve to the right, suggesting a delay in the expression of all causes of mortality. BM survived 186 days longer than controls. Furthermore, the body weight was significantly lower in the BM as compared with the controls at 20 months after birth (P < 0.05), and leukocyte composition analysis at 8 weeks revealed that the eosinophil count was significantly increased in the BM as compared with the controls (P < 0.05, n = 6).
These findings demonstrate that the maternal genome may play a role in ontogenetic longevity. Our results further suggested sex differences in longevity, originating at the genome level, implying that the sperm genome has a detrimental effect on longevity in mammals.
在包括人类在内的许多哺乳动物物种中，女性的寿命比男性长。人们观察到，在寿命方面，女性比男性具有优势；然而，这种长寿性别差异的原因尚不清楚。通过“无精子”方式产生的双母体（BM）小鼠，为分析缺乏父本基因组的动物的寿命提供了机会。
我们研究了 BM 的寿命，这些 BM 是使用两组女性基因组产生的——一组来自正常成年的完全成熟卵母细胞，另一组来自新生幼崽的非生长卵母细胞。这些新生幼崽还在两条染色体 7 和 12 上的印记中心 Igf2-H19 和 Dlk1-Gtl2 两个区域进行了基因操作。我们确定了对照组（n=13）和 BM 组（n=13）的寿命。我们的结果表明，双母体基因型明显将整个存活曲线向右移动，表明所有死亡原因的表达都延迟了。BM 的存活时间比对照组长 186 天。此外，与对照组相比，BM 的体重在出生后 20 个月时显著降低（P < 0.05），白细胞组成分析显示，BM 中的嗜酸性粒细胞计数明显高于对照组（P < 0.05，n=6）。
这些发现表明母体基因组可能在个体发育的长寿中发挥作用。我们的结果进一步表明，起源于基因组水平的长寿存在性别差异，这意味着精子基因组对哺乳动物的长寿有不利影响。
