Sager R, Lane D
Proc Natl Acad Sci U S A. 1972 Sep;69(9):2410-3. doi: 10.1073/pnas.69.9.2410.
The mechanism of preferential transmission (i.e., maternal inheritance) of cytoplasmic genes was investigated with chloroplast DNA of Chlamydomonas as a model system. The behavior of nuclear and chloroplast DNAs were compared in the sexual cycle; DNAs from male and female parents were distinguished by labeling with (14)N- or (15)NH(4)Cl and then by making the crosses: (14)N (female) x (15)N (male) and the reciprocal. Chloroplast DNAs from the two parents followed different paths in the zygote, but nuclear DNAs showed no differences. Chloroplast DNA from the female parent persists in the zygote, but undergoes a density shift of 0.003-0.005 g/cm(3) to a lighter buoyant density, whereas that from the male disappears soon after zygote formation. The possibility is discussed that a modification-restriction system may be involved.
以衣藻的叶绿体DNA作为模型系统，研究了细胞质基因的优先传递机制（即母系遗传）。在有性生殖周期中比较了核DNA和叶绿体DNA的行为；通过用(14)N-或(15)NH(4)Cl标记区分来自雄性和雌性亲本的DNA，然后进行杂交：(14)N（雌性）×(15)N（雄性）及其反交。来自双亲的叶绿体DNA在合子中遵循不同的路径，但核DNA没有差异。来自雌性亲本的叶绿体DNA在合子中持续存在，但经历了0.003 - 0.005 g/cm(3)的密度变化，变为较轻的浮力密度，而来自雄性亲本的叶绿体DNA在合子形成后不久就消失了。文中讨论了可能涉及修饰 - 限制系统的可能性。
