| Chagas disease,also known as American trypanosomiasis,is an important parasitic disease affecting public health in the Latin America,with a disease burden that can be up to five times that of malaria in disabilities-adjusted years.As the global process has accelerated,the disease has spread from endemic areas(Latin America)to non-endemic areas(Australia,Africa,Asia,etc.).So far,no Chagas disease case has been reported in China.However,in China,the presence of two species of Triatoma(T.rubrofasciata and T.sinica Hsiao)was recorded in the past and T.rubrofasciata has been confirmed as one of the vectors of Chagas disease,so it was important to study on T.rubrofasciata for the future importation of Chagas disease into China.Since 2016,an investigation has been carried out on the distribution of T.rubrofasciata in China,The results showed that T.rubrofasciata was found in many areas of Guangdong,Guangxi,Fujian and Hainan provinces,but the ecological environment of each region was not exactly the same.The research showed that other bugs in different ecological zones produced differences in morphology,genetics.However,the genetic differentiation of T.rubrofasciata among different ecological zones in China is not clear.This research mainly studied on the genetic differentiation of T rubrofasciata from the aspects of morphology,cytology and molecular biology in different ecological zones in China.First part,Morphological differences of T.rubrofasciata in China and its correlation with environmental and climatic factorsObjective To explore the morphological differences of T.rubrofasciata samples from different ecological zones in China and the correlation between environmental climate factors and morphological differences in different ecological zones.Methods Collecting T.rubrofasciata samples from Baoting,Changjiang,Chongzuo,Zhanjiang,Shunde,and Zhangzhou and measuring 7 groups morphological data of each specie.The differences of morphological parameters among different ecological regions zones were analyzed by SPSS.At the same time,ArcGIS was used to extract the ecological environmental factors(temerature related factors and humidity related factors)?altitude and longitude information of each sampling sites.SPSS software was used to explore the correlation between morphological parameters and altitude/latitude,temperature related factors and humidity related factors of T.rubrofasciata samples from different ecological regions zones.Results There were significant differences in body size among different ecological regions,among which the morphological parameters from Changjiang(Hainan Huandao Tropical Agricultural Ecological Zone)and Baoting(Hainan Central Mountainous Tropical Rainforest and Seasonal Rainforest Ecological Zone)were the largest.The relationship between the morphological parameters and latitude was U-shaped,that is,when the latitude ranged from 18N° to 24N°,the morphological parameters first decreased and then increased with the increase of latitude,but the relationship between the morphological parameters and altitude was not obvious.Morphological parameters of T.rubrofasciata were positively correlated with temperature in all ecological regions,that is,with the increase of temperature,7 morphological parameters of T.rubrofasciata also increased.Morphological parameter values of Trubrofasciata in each ecological area had the greatest relationship with humidity related factor BIO14,showing a negative correlation,that is,with the increase of humidity,the morphological parameter values of T.rubrofasciata decreased.Second part C-band karyotype analysis of T.rubrofasciata in ChinaObjective To explore the differences in chromosome level of male Trubrofasciata samples from different regions in China.Methods Using C-band technique to explore the chromosome of male T.rubrofasciata samples from China to obtaining chromosomal-related parameters,and analying chromosome types,chromosomal behavior.Result There is no obvious difference in number and behaviour of chromosomes from male T.rubrofasciata with different sources.It can be seen under the microscope that there were 25 chromosomes in male T.rubrofasciata,among them,22 chromodomes are autosomes,the other three ones are sex chromosome-Xi,X2,Y.In three sex chromosomes,the size of Y chromosome is obviously larger than that of X chromosome,and the size of X1 and X2 are similar.After measurement and calculation,all chromosomes belong to m type chromosome.The karyotype composition of male T.rubrofasciata in China is:2n=22m+X1X2Y.Third part Population genetic differentiation of T.rubrofasciata from China based on 16S rRNA,18S rRNA,COl,etc gene molecular markerObjective To explore the genetic differentiation at DNA level of T.rubrofasciata samples from different regions in China.Methods The nuclear gene(18S rRNA,28S rRNA)and mitochondrial gene(16SrRNA,Cytb,CO1)sequences of 210 T.rubrofasciata samples collected from 10 sampling sites in Fujian,Hainan,Guangxi and Guangxi provinces were measured.DnaSP was used to calculate the genetic diversity of CO1 and Cytb of samples from each region,and MEGA6 software was used to construct the phylogenetic tree of samples from each region.After that,the five genes were combined,the haplotype Network map was constructed using the Network software,and the population Structure map was constructed using the structure software at the same time.Results Phylogenetic analysis of five genes and genetic diversity analysis of CO1 and Cytb indicated that the T.rubrofasciata from different ecological regions in China were closely related and had low level of genetic differentiation.The results of population structure analysis showed that T.rubrofasciata samples from four regions with higher latitudes(Zhangzhou,Chongzuo,Shunde and Guangzhou)and three regions with lower latitudes(Baoting,Maoming and Zhanjiang)belonged to two different populations. |
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