Characterization Of The Chromosome Karyotype And Number Of Parascaris Spp.and Ascaris Suum

Parascaris spp.and Ascaris suum are typical representatives of the Ascarididae,which are a serious threat to the life and health of equids as well as pigs.The infection of these worms can lead to intestinal blockage or even intestinal rupture,which can directly lead to the death of the host in severe cases.Chromosomes are the carriers of eukaryotic genetic material,but there are few studies on the chromosomes of roundworms.Understanding the chromosome haplotypes of these roundworms is necessary to resolve the biological properties of these species.Applying genomic techniques to chromosomes and different chromosome numbers to species identification will positively affect the systematic classification of roundworms.To investigate the differences in chromosome numbers and changes in characteristics of different roundworms.In this study,we first observed the chromosomal status of different ascarids during development;secondly,we classified Parascaris spp.according to chromosome number differences and verified it using morphological identification and phylogenetic analysis.Finally,the genome of A.suum was assembled and annotated using third-generation sequencing technology.The chromosome number and sex chromosome composition of A.suum were determined by Hi-C chromosome conformation capture technology.The specific research results are as follows:1.Parascaris spp.were divided into two species based on differences in chromosome number,P.univalens in horses and zebras with two chromosomes,Parascaris sp.in donkeys with six chromosomes verified using partial structural differences in egg and phylogenetic analysis.Additionally,it was determined that all Parascaris eggs have chromosome breaks during development.2.The chromosome number of A.suum cannot be known by karyotype.In this study,the genome size of A.suum was approximately 265.5 Mb.The chromosome number of A.suum was confirmed to be 19 autosomes and 5 sex chromosomes by chromosome conformation capture technique,and the genetic basis for determining the sex of A.suum was determined to be XX/XO.In summary,this study used the technology of egg culture,karyotype identification,phylogenetic analysis and third-generation sequencing to determine that P.univalens has 2chromosomes,Parascaris sp.has 6 and A.suum has 24;Confirm the importance of chromosome number in the taxonomy of Parascaris spp.;It was determined that the chromosomal basis for the sex determination of A.suum is XX/XO.