Sequence variation in two mitochondrial DNA regions and internal transcribed spacer among isolates of the nematodeOesophagostomum asperumoriginating from goats in Hunan Province, China

Abstract

The present study examined sequence variability in two mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1), and internal transcribed spacer (ITS) of nuclear ribosomal DNA (rDNA) among Oesophagostomum asperum isolates from goats in Hunan Province, China. A portion of the cox1 (pcox1), nad1 (pnad1) genes and the ITS (ITS1+5.8S rDNA+ITS2) rDNA were amplified by polymerase chain reaction (PCR) separately from adult O. asperum individuals and the representative amplicons were subjected to sequencing from both directions. The lengths of pcox1, pnad1 and ITS rDNA were 366 bp, 681 bp and 785 bp, respectively. The A+T contents of gene sequences were 71.5-72% for pcox1, 73.7-74.2% for pnad1 and 58-58.8% for ITS rDNA. Intra-specific sequence variations within O. asperum were 0-1.6% for pcox1, 0-1.9% for pnad1 and 0-1.7% for ITS rDNA, while inter-specific sequence differences among members of the genus Oesophagostomum were significantly higher, being 11.1-12.5%, 13.3-17.7% and 8.5-18.6% for pcox1, pnad1 and ITS rDNA, respectively. Phylogenetic analyses using combined sequences of pcox1 and pnad1, with three different computational algorithms (Bayesian inference, maximum likelihood and maximum parsimony), revealed distinct groups with high statistical support. These findings demonstrated the existence of intra-specific variation in mtDNA and rDNA sequences among O. asperum isolates from goats in Hunan Province, China, and have implications for studying molecular epidemiology and population genetics of O. asperum.

COX1 gene and ITS-2 region: A comparative study of molecular diagnosis of Parabronema skrjabini in camels (Camelus dromedaries), Al-Najaf Province, Iraq

“…The phylogenetic tree showed the relationship with species Habronema sp. at an early evolutionary period, this is also similar to the another spirurida, confirming the results of the previous studies as" a typical marker for determining evolutionary history" (27), analysis of the phylogenetic among other species in relation to multiple branches within a monophyletic group. We determined the few substitutions of the related species in a family Habeonematidae depend on COX1 mtDNA gene, that related to a separate branch during an early evolutionary time; if reported the substitution number of 9-12/per local isolate (the substitution ratio about 1.98-2.6%)with H. muscae KX868085, then an increase in the mutations are reached 15.26% towards the early position according to the (Table 8),when comparing the substitution and identical ratios indicated for them in the results chapter between the local isolates both genes.…”

“…The multiple sequence alignment showed the a clear variation of ITS2rDNA region in P.skrjabini according to the sequences published in NCBI website, the mutation ratio reached 13.4% with Basra isolates taken from the small ruminants and the relatively less to the substitutions level has 8% of H. muscae (donkey) or P.smithi about 5.9% of early common ancestor, consequently, it is confirming the idea of P. skrjabini carries a unique pattern of the ITS2rDNA gene sequence. In the previous studies, the mitochondrial DNA variation within members of the same species was indicated 2-6% such as Ostertagia ostertagi (27). The mitochondrial DNA sequence of the related species range 10-20%; therefore, every two members may be a difference within 10% or more (27).…”

“…As a result of the sequence and phylogenetic data for each of the genetic markers, the ITS2rDNA gene has a fixed pattern of Indels (a common feature of ITS2rDNA region) and the similar model of the sequence differences presented the high conservative pattern of the same species, if the divergence level 1% among the individuals (26,27), thus able to identifying at the lower categorical levels as called the deep levels e.g. species and populations (28).…”

“…The mitochondrial DNA sequence of the related species range 10-20%; therefore, every two members may be a difference within 10% or more (27). The mitochondrial COX1gene has introduced a clear picture in recognizing the genetic individual variation mapping lead to determining for the cryptic species within known nematode, which not confirmed by the results of the current study (27), the sequences are appeared for all local isolate early related to a most common ancestor with Chinese isolates Habronema muscae and, H. majus.…”

Comparison of the first time detected Oesophagostomum asperum with Oesophagostomum columbianum in sheep and goats in Bangladesh based on the trinity: Morphology, morphometry and genetic diversity

“…When the study sequences were compared with reference sequences from China, Japan and Australia from BLAST search, sequence identities ranged from 97 to 100 % ( NCBI, 2022 ). Distinguished morphological characters of these two study species is proved by very high intra specific variation (19.5–20.1 %) between them which is supported by Hu et al, (2014) and Li et al, (2016) . Furthermore, slightly higher sequence diversity has also been reported by Jia et al, (2014) and Zhao et al, (2014) .…”