scholarly journals A new method for estimating the demographic history from DNA sequences: an importance sampling approach

2015 ◽  
Vol 6 ◽  
Author(s):  
Sadoune Ait Kaci Azzou ◽  
Fabrice Larribe ◽  
Sorana Froda
Keyword(s):  
Importance Sampling ◽  
Dna Sequences ◽  
Demographic History ◽  
New Method ◽  
Sampling Approach

A new method to analyze the similarity of the DNA sequences

2008 ◽  
Vol 853 (1-3) ◽  
pp. 62-67 ◽  
Author(s):  
Ying Guo ◽  
Tian-ming Wang
Keyword(s):  
Dna Sequences ◽  
New Method

scholarly journals Molecular characterization and genetic diversity of Ornithonyssus sylviarum in chickens (Gallus gallus) from Hainan Island, China

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Biswajit Bhowmick ◽  
Jianguo Zhao ◽  
Øivind Øines ◽  
Tianlin Bi ◽  
Chenghong Liao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Genetic Diversity ◽  
Molecular Analysis ◽  
Dna Sequences ◽  
Demographic History ◽  
Asian Countries ◽  
Ornithonyssus Sylviarum ◽  
Private Haplotype ◽  
Northern Fowl Mite ◽  
Poultry Farms

Abstract Background The northern fowl mite (NFM), Ornithonyssus sylviarum, is an obligatory hematophagous ectoparasite of birds and one of the most important pests in the poultry industry on several continents. Although NFM poses a serious problem, it remains a neglected pest of poultry in China and other Asian countries. Therefore, a molecular analysis was conducted to provide baseline information on the occurrence, genetic diversity and emergence of NFM in poultry farms from China. Methods This study focused on morphological description and identification of adults based on electron microscopy, molecular sequencing of the mitochondrial cox1 gene and phylogenetic analysis. We have also used the DNA sequences of the cox1 gene to study the genetic diversity, population structure and demographic history. The neutrality tests were used to analyze signatures of historical demographic events. Results The mites collected were identified as the northern fowl mite Ornithonyssus sylviarum based on external morphological characterization using electron microscopy. Molecular analysis using a 756-bp long partial fragment of the cox1 gene revealed 99–100% sequence identity with NFM and phylogenetic inferences showed a bootstrap value of 99% indicating a well-supported monophyletic relationship. Molecular diversity indices showed high levels of haplotype diversity dominated by private haplotypes, but low nucleotide divergence between haplotypes. The Tajima’s D test and Fu’s Fs test showed negative value, indicating deviations from neutrality and both suggested recent population expansion of mite populations supported by a star-like topology of the isolates in the network analysis. Our genetic data are consistent with a single introduction of NFM infestations and the spread of NFM infestation in Hainan poultry farms and a private haplotype dominance, which suggest that infestations are recycled within the farms and transmission routes are limited between farms. Conclusions To our knowledge, this is the first time a molecular report of NFM in chicken from China including other Asian countries using DNA barcoding. The findings have potential implications with respect to understanding the transmission patterns, emergence and populations trends of parasitic infestations of poultry farms that will help for setting the parameters for integrated pest management (IPM) tactics against mite infestations.

Chance-constrained problems and rare events: an importance sampling approach

2015 ◽  
Vol 157 (1) ◽  
pp. 153-189 ◽  
Author(s):  
Javiera Barrera ◽  
Tito Homem-de-Mello ◽  
Eduardo Moreno ◽  
Bernardo K. Pagnoncelli ◽  
Gianpiero Canessa
Keyword(s):  
Importance Sampling ◽  
Rare Events ◽  
Constrained Problems ◽  
Sampling Approach
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