Construction Of A High-resolution Chromosome Map And Physical Map For Anopheles Sinensis

Anopheles sinensis belongs to Hyrcanus group in genus Anopheles and subgenus Anopheles.As an important epidemic vector with widely geographic distribution in China,it can transmit Plasmodium vivax and Brugia malayi.In addition to be a significant malaria vector,An.sinensis is also an excellent model system for polytene chromosome study,since high-quality chromosomes are present in the salivary gland from forth-instar larvae of this species.Previously published chromosome maps for An.sinensis have been extensively used for the identification of closely-related species and studies of the genetic contents concerning the difference on their capability of ecological adaptation and malaria transmission.However,the low resolution of those maps has limited studies in taxonomy.Recently,the launch of Anopheles genome projects and the release of several genome databases for An.sinensis Korea strain and China strain make the development of a physical map for this species timely and important.An.lesteri and An.sinensis are sibling species within the An.hycanus group and it is extremely difficult to separate them due to their identical morphological characteristics.Despite being morphologically indistinguishable,An.lesteri and An.sinensis differ strongly in geographic distribution and malaria transmission.An.sinensis is the most widespread species,whose range is continuous throughout the region excluding Qinghai and Xinjiang provinces in china,while An.lesteri is only limited to central and southeast of china.What is more,An.Lesteri,which is the principle cause of outbreak of malaria in china,transmits malaria more efficiently than An.sinensis.In this study,we developed a high-resolution polytene chromosome map,which was divided into 39 numbered divisions and 116 lettered subdivisions,for An.sinensis from the salivary glands.We also described one polymorphic paracentric chromosomal inversion on 3R arm and mapped the breakpoints to subdivisions 28A and 31A to promote the research of population genetics.In order to map the published scaffolds to polytene chromosomes of An.sinensis,we roughly constructed a physical map for this species with 52 DNA markers.Finally,a comparison of the physical map for An.sinensis with that for An.gambiae revealed a whole-arm autosomal translocation between these two species.Specifically,the 2R arm of An.gambiae corresponds to the 3R arm of An,sinensis,while the rest chromosomal arms are conserved.The standard cytogenetic map and a well-developed physical map for An.sinensis in this study will provide useful information for the studies of insect taxonomy,population genetics,ecological genetics and chromosomal evolution.To find an efficient and simple identification method for An.lesteri and An.sinensis,as well as to accelerate the study of genetic contents associated with ecological distribution and malaria transmission,we have developed a high-resolution cytogenetic map for An.lesteri with 39 numbered divisions and 116 lettered subdivisions.Meanwhile,the chromosomal localizations of 24 conserved DNA probes from the genome of An.sinensis were determined by fluorescent in situ hybridization.The comparisons of the banding patterns and chromosomal locations of conserved DNA markers have revealed both of species share similar chromosomes and five chromosomal arms are conserved.Moreover,we also found two polymorphic inversions on 2L(2La)and 3R(3Ra)arms of An.lesteri,and mapped them to the chromosome map.These results will provide valuable information for cytogenetic studies of An.lesteri and An.sinensis,and build a solid foundation for the study of molecular mechanisms of ecological adaptation and malaria transmission.