Bonen L, Cunningham R S, Gray M W, Doolittle W F
Nucleic Acids Res. 1977 Mar;4(3):663-71. doi: 10.1093/nar/4.3.663.
We present a catalog of sequences of oligonucleotides produced by T1 ribonuclease digestion of 32P-labeled small-ribosomal-subunit RNA ("18S rRNA) isolated from purified wheat embryo mitochondria. This catalog is compared to catalogs published for prokaryotic and chloroplast 16S rRNAs and to preliminary results for wheat cytosol 18S rRNA. These comparisons indicate that: (1) wheat mitochondrial 18S rRNA is clearly prokaryotic in nature, showing significantly more sequence homology with 16S rRNAs than can be expected to arise by chance (p less than 0.000001); (2) shared oligonucleotide sequences include an especially high proportion of those identified as conserved in the evolution of prokaryotic rRNAs; and (3) wheat embryo mitochondrial and cytosol 18S rRNAs retain no more, and perhaps less, than the minimum sequence homology detectable by this sensitive method. These results argue in favor of an endosymbiotic origin for mitochondria.
我们展示了一份寡核苷酸序列目录，这些序列是通过对从纯化的小麦胚线粒体中分离出的经32P标记的小核糖体亚基RNA（“18S rRNA”）进行T1核糖核酸酶消化产生的。该目录与已发表的原核生物和叶绿体16S rRNA目录以及小麦细胞质18S rRNA的初步结果进行了比较。这些比较表明：（1）小麦线粒体18S rRNA在本质上显然是原核生物的，与16S rRNA的序列同源性明显高于偶然出现的预期（p小于0.000001）；（2）共享的寡核苷酸序列中，在原核生物rRNA进化过程中被鉴定为保守的序列所占比例特别高；（3）小麦胚线粒体和细胞质18S rRNA保留的序列同源性不超过，甚至可能少于这种灵敏方法可检测到的最小序列同源性。这些结果支持线粒体的内共生起源。
