Division of Parasitology, ICAR- Indian Veterinary Research Institute, Izatnagar, U.P., India.
Division of Parasitology, ICAR- Indian Veterinary Research Institute, Izatnagar, U.P., India; Department of Veterinary Parasitology, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India.
Acta Trop. 2021 Dec;224:106121. doi: 10.1016/j.actatropica.2021.106121. Epub 2021 Sep 2.
The present study describes the genetic diversity in the Tams1 gene (733 bp) of Theileria annulata along with the sequence, phylogenetic and haplotype analyses of the Indian isolates. The phylogenetic analyses displayed distinct clustering of the Indian isolates into three groups suggesting the presence of three genotypes, hitherto designated as T. annulata genotypes 1-3 (G1-G3). Genotype 3 seems to be novel containing only two newly generated sequences. Indian isolates displayed 88.4-100% and 82.2-100% similarity with each other at nucleotide (nt) and amino acid (aa) levels, respectively. However, the newly generated sequences (n = 36) showed 90.5-100% and 84.3-100% identity between them at nt and aa levels, respectively. The most diverse and heterogeneous genotype, G1, exhibited the highest number of polymorphic sites (S = 148), haplotypes (h = 16) and nucleotide differences (k = 43.23) besides haplotype (Hd = 0.903 ± 0.031) and nucleotide (π = 0.059 ± 0.005) diversities. Neutrality indices suggested a respective decrease and increase in population sizes of G1 and G2 genotypes in India. The nucleotide sequence analyses indicated the presence of extensive sequence variations between nucleotide positions 1-124, 194-257 and 396-494. The N-terminus of Tams1 protein displayed a considerable sequence variability with extensive variations in two regions, between amino acid positions 1-39 and 127-172, as compared to the conserved carboxyl terminus.
本研究描述了环形泰勒虫 Tams1 基因（733bp）的遗传多样性，以及印度分离株的序列、系统发育和单倍型分析。系统发育分析显示，印度分离株明显分为三组，提示存在三种基因型，以前称为环形泰勒虫基因型 1-3（G1-G3）。基因型 3似乎是新的，仅包含两个新生成的序列。印度分离株在核苷酸（nt）和氨基酸（aa）水平上彼此显示 88.4-100%和 82.2-100%的相似性。然而，新生成的序列（n=36）在 nt 和 aa 水平上彼此显示 90.5-100%和 84.3-100%的同一性。最多样化和异质的基因型 G1 表现出最高数量的多态性位点（S=148）、单倍型（h=16）和核苷酸差异（k=43.23），此外还有单倍型（Hd=0.903±0.031）和核苷酸（π=0.059±0.005）多样性。中性指数表明，G1 和 G2 基因型在印度的种群规模分别相应减少和增加。核苷酸序列分析表明，在核苷酸位置 1-124、194-257 和 396-494 之间存在广泛的序列变异。Tams1 蛋白的 N 端显示出相当大的序列变异性，在两个区域（氨基酸位置 1-39 和 127-172）之间存在广泛的变异，与保守的羧基末端相比。
