Larval stages of the camel nasal botfly, Cephalopina titillator (Diptera: Oestridae), rank among the top obligate endoparasites causing nasopharyngeal myiasis. Such infestations have adverse effects on camel health, reducing their economic value. The current study’s objective is to assess the applicability of PCR using partial regions of the COI mtDNA and 28S rRNA gene sequences to identify, classify, and reveal the phylogenesis of C. titillator. Larvae of the 2nd and 3rd instars of C. titillator were collected from the El-Bassatin abattoir in Egypt, extracted from the nasopharyngeal passage of the Arabian camel (Camelus dromedarius) during postmortem inspection. Genomic DNA was successfully isolated from 10 samples of 3rd instar larvae of C. titillator and amplified using primer pairs targeting partial mitochondrial COI (916 bp) and ribosomal 28S rRNA (830 bp) gene fragments. Nucleotide sequences from five samples have been sequenced and submitted to GenBank under accession numbers OP482168 to OP482172 for the COI gene and OP482160 to OP482164 for the 28S rRNA gene fragments. The COI gene exhibited 97.3% nucleotide identity across all specimens, while the 28S rRNA gene displayed 99.74% identical nucleotides. Maximum likelihood trees were constructed based on the generalized time-reversible (GTR) model. The resulting COI phylogenetic tree demonstrated that the subfamily Oestrinae does not exhibit monophyly. Additionally, it revealed that C. titillator is a sister group to the subfamily Gasterophilinae. Despite the scarcity of data available for the 28S rRNA gene, the phylogenetic analysis utilizing 28S rRNA revealed one distinct lineage for the Egyptian camel nasal bot fly. Molecular phylogenetic analysis was conducted using molecular markers of distinct origins (both mitochondrial and nuclear) to elucidate the evolutionary relationships within the family Oestridae. This analysis is particularly significant following the inclusion of C. titillator, a first-time discovery in Egypt.

中文翻译：

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骆驼鼻蝇、头蝇（双翅目：Oestridae）的分子特征

骆驼鼻蝇（双翅目：蝇科）的幼虫阶段是导致鼻咽蝇蛆病的顶级专性内寄生虫之一。这种感染对骆驼的健康产生不利影响，降低其经济价值。当前研究的目的是评估使用 COI mtDNA 和 28S rRNA 基因序列的部分区域进行 PCR 来识别、分类和揭示 C. titilator 系统发育的适用性。C. titilator 的 2 龄和 3 龄幼虫是从埃及 El-Bassatin 屠宰场采集的，是在尸检过程中从阿拉伯骆驼 (Camelus dromedarius) 的鼻咽通道中提取的。从 10 个 C. titilator 3 龄幼虫样本中成功分离出基因组 DNA，并使用针对部分线粒体 COI (916 bp) 和核糖体 28S rRNA (830 bp) 基因片段的引物对进行扩增。来自五个样品的核苷酸序列已被测序并提交给 GenBank，COI 基因的登录号为 OP482168 至 OP482172，28S rRNA 基因片段的登录号为 OP482160 至 OP482164。COI 基因在所有样本中显示出 97.3% 的核苷酸同一性，而 28S rRNA 基因显示出 99.74% 的核苷酸同一性。最大似然树是基于广义时间可逆（GTR）模型构建的。由此产生的 COI 系统发育树表明，Oestrinae 亚科并不表现出单系性。此外，它还表明 C. titilator 是 Gasterophilinae 亚科的姐妹群。尽管 28S rRNA 基因的可用数据很少，但利用 28S rRNA 进行的系统发育分析揭示了埃及骆驼鼻蝇的一个独特谱系。使用不同起源（线粒体和细胞核）的分子标记进行分子系统发育分析，以阐明 Oestridae 家族内的进化关系。在埃及首次发现 C. titilator 后，这项分析显得尤为重要。