Abstract：
Insect mitochondrial genomes (mitogenomes) are usually represented by a conserved gene order. Whiteflies exhibit gene rearrangement in their mitogenomes; however, understanding how nucleotide substitution rates shape gene rearrangement in whiteflies is unclear due to the limited number of mitogenomes. Additionally, the mechanisms by which selection pressure drives adaptations in mitochondrial genes in the two subfamilies of whiteflies are not yet known. Here, we analyzed 18 whitefly mitogenomes, including one newly generated mitogenome, to compare nucleotide substitution rates, selection pressure, and gene arrangements. The newly generated mitogenome is reported along with reannotation of Pealius mori and comparisons to other whitefly mitogenomes. Comparative studies on nucleotide composition of 18 whiteflies revealed the positive GC skewness, confirming the reversal of strand asymmetry. We found 11 rearranged gene orders within two subfamilies of whiteflies with 8-18 breakpoints of gene rearrangements. Members of the subfamily Aleyrodinae exhibit more complex pathways in the evolution of gene order as compared to the subfamily Aleurodicinae. Our findings also revealed that the increase or reduction of nucleotide substitution rates does not have an impact on any of the gene rearrangement scenarios depicting neutral correlation. Selection pressure analysis revealed that the mitogenomes from members of both the subfamilies Aleurodicinae and Aleyrodinae are characterized by intense purifying selection pressure.
摘要：
昆虫线粒体基因组(有丝分裂基因组)通常由保守的基因顺序表示。粉虱在其有丝分裂基因组中表现出基因重排；然而，由于有丝分裂基因组的数量有限，尚不清楚核苷酸取代率如何影响粉虱的基因重排。此外,选择压力驱动两个粉虱亚家族线粒体基因适应的机制尚不清楚。这里,我们分析了18个粉虱有丝分裂基因组，包括一个新产生的有丝分裂基因组,为了比较核苷酸取代率，选择压力,和基因安排。报道了新产生的有丝分裂基因组，以及对香皮的重新注释以及与其他粉虱有丝分裂基因组的比较。对18只粉虱的核苷酸组成的比较研究表明，GC偏度为正，确认链不对称的逆转。我们在两个粉虱亚家族中发现了11个重排的基因顺序，具有8-18个基因重排断点。与亚科Aleurodicinae相比，亚科Aleyrodinae的成员在基因顺序的进化中表现出更复杂的途径。我们的发现还表明，核苷酸取代率的增加或减少对描述中性相关性的任何基因重排方案都没有影响。选择压力分析显示，来自Aleurodicinae和Aleyrodinae亚家族成员的有丝分裂基因组的特征在于强烈的纯化选择压力。
