Mikac K M, Fitzsimmons N N
Institute for Applied Ecology, University of Canberra, Bruce, ACT, 2601, Australia.
Bull Entomol Res. 2010 Oct;100(5):521-7. doi: 10.1017/S0007485309990538. Epub 2010 Feb 2.
Microsatellite markers were used to investigate the genetic structure among invasive L. decolor populations from Australia and a single international population from Kansas, USA to determine patterns of dispersal. Six variable microsatellites displayed an average of 2.5-4.2 alleles per locus per population. Observed (HO) heterozygosity ranged from 0.12-0.65 per locus within populations; but, in 13 of 36 tests, HO was less than expected. Despite low levels of allelic diversity, genetic structure estimated as theta was significant for all pairwise comparisons between populations (theta=0.05-0.23). Due to suspected null alleles at four loci, ENA (excluding null alleles) corrected FST estimates were calculated overall and for pairwise population comparisons. The ENA-corrected FST values (0.02-0.10) revealed significant overall genetic structure, but none of the pairwise values were significantly different from zero. A Mantel test of isolation by distance indicated no relationship between genetic structure and geographic distance among all populations (r2=0.12, P=0.18) and for Australian populations only (r2=0.19, P=0.44), suggesting that IBD does not describe the pattern of gene flow among populations. This study supports a hypothesis of long distance dispersal by L. decolor at moderate to potentially high levels.
微卫星标记被用于研究来自澳大利亚的入侵性脱色丽蝇种群和来自美国堪萨斯州的单一国际种群之间的遗传结构，以确定扩散模式。六个可变微卫星在每个种群的每个位点平均显示2.5 - 4.2个等位基因。种群内每个位点的观察杂合度（HO）范围为0.12 - 0.65；但是，在36次测试中的13次中，HO低于预期。尽管等位基因多样性水平较低，但作为θ估计的遗传结构在种群间的所有成对比较中都很显著（θ = 0.05 - 0.23）。由于怀疑四个位点存在无效等位基因，总体上以及对成对种群比较计算了排除无效等位基因的ENA校正FST估计值。ENA校正后的FST值（0.02 - 0.10）显示出显著的总体遗传结构，但成对值中没有一个与零有显著差异。距离隔离的Mantel检验表明，所有种群之间（r2 = 0.12，P = 0.18）以及仅澳大利亚种群之间（r2 = 0.19，P = 0.44）的遗传结构与地理距离之间没有关系，这表明距离隔离不能描述种群间的基因流动模式。这项研究支持了脱色丽蝇在中等到潜在高水平的长距离扩散假说。
