Jung S, Tate P L, Horn R, Kochert G, Moore K, Abbott A G
Department of Genetics and Biochemistry, Clemson University, 100 Jordan Hall, Clemson, SC 29634-0324, USA.
J Hered. 2003 Jul-Aug;94(4):334-40. doi: 10.1093/jhered/esg061.
The cultivated peanut (Arachis hypogaea L.) is an allotetraploid composed of A and B genomes. The phylogenetic relationship among the cultivated peanut, wild diploid, and tetraploid species in the section Arachis was studied based on sequence comparison of stearoyl-ACP desaturase and oleoyl-PC desaturase. The topology of the trees for both fatty acid desaturases displayed two clusters; one cluster with A genome diploid species and the other with B genome diploid species. The two homeologous genes obtained for each of the two fatty acid desaturases from the tetraploid species A. hypogaea and A. monticola were separated into the A and B genome clusters, respectively. The gene phylogenetic trees showed that A. hypogaea is more closely related to the diploid species A. duranensis and A. ipaensis than to the wild tetraploid species A. monticola, suggesting that A. monticola is not a progenitor of the cultivated peanut. In addition, for the stearoyl-ACP desaturase, the A. duranensis sequence was identical with one of the sequences of A. hypogaea and the A. ipaensis sequence was identical with the other. These results support the hypothesis that A. duranensis and A. ipaensis are the most likely diploid progenitors of the cultivated tetraploid A. hypogaea.
栽培种花生（Arachis hypogaea L.）是一种由A和B基因组组成的异源四倍体。基于硬脂酰-ACP去饱和酶和油酰-PC去饱和酶的序列比较，研究了花生属中栽培种花生、野生二倍体和四倍体物种之间的系统发育关系。两种脂肪酸去饱和酶的树状图拓扑结构显示出两个聚类；一个聚类包含A基因组二倍体物种，另一个聚类包含B基因组二倍体物种。从四倍体物种A. hypogaea和A. monticola中获得的两种脂肪酸去饱和酶各自的两个同源基因分别被归入A和B基因组聚类中。基因系统发育树表明，A. hypogaea与二倍体物种A. duranensis和A. ipaensis的亲缘关系比与野生四倍体物种A. monticola的更近，这表明A. monticola不是栽培种花生的祖先。此外，对于硬脂酰-ACP去饱和酶，A. duranensis的序列与A. hypogaea的一个序列相同，而A. ipaensis的序列与另一个相同。这些结果支持了A. duranensis和A. ipaensis是栽培四倍体A. hypogaea最可能的二倍体祖先这一假说。
