Genetic diversity and population structure of <i>Irvingia species</i> using DArTseq generated markers

<i>Irvingia gabonensis</i> and <i>Irvingia wombolu</i> trees indigenous to West and Central Africa are economically important owing to their valuable kernels. Massive fruit harvesting and reduction of forests land area has threatened their genetic diversity thus warranting conservation. This study reports the genetic diversity and population structure based on dominant markers of Irvingia accessions from Nigeria, Cameroon and Gabon held at World Agroforestry field genebanks. A total of 60 samples and 6532 SilicoDArT markers revealed high genetic differentiation among populations (phiPT = 0.301, P = .001). The overall genetic diversity revealed by Nei’s gene diversity (He = 0.117) and percentage of polymorphic loci (39.60%) was low. <i>I.gabonensis</i> provenances from Cameroon and Nigeria were more diverse than Gabonese populations. Pairwise phiPT values calculated from AMOVA variances delineated <i>I. wombolu</i> and <i>I. gabonensis</i>. Population structure and cluster analysis based on Bayesian algorithm, DAPC and UPGMA methods placed Cameroon at the center of distribution of <i>I. gabonensis</i> accessions from Nigeria and Gabon. Gabonese accessions tend to cluster independent of Nigerian accessions while <i>I. wombolu</i> formed a distinct cluster from <i>I. gabonensis</i>. SilicoDArT markers were found suitable for population structure and differentiation analysis of Irvingia accessions and can guide future recollections to enrich genebank diversity and materials for domestication events.

原产于西非和中非的加蓬榄（Irvingia gabonensis）与温博勒榄（Irvingia wombolu），因其富含经济价值的果仁而具备重要经济地位。大规模果实采收与林地面积缩减已对其遗传多样性造成严重威胁，因此亟需开展针对性保护工作。本研究针对保存于世界农林业（World Agroforestry）田间基因库的尼日利亚、喀麦隆及加蓬的榄属（Irvingia）种质材料，基于显性标记开展遗传多样性与种群结构分析。本研究共纳入60份样本与6532个SilicoDArT标记（SilicoDArT markers），结果显示种群间存在高度遗传分化（phiPT=0.301，P=0.001）。通过Nei's基因多样性（Nei’s gene diversity，He=0.117）与多态位点百分比（39.60%）所反映的整体遗传多样性水平较低。其中，喀麦隆与尼日利亚的加蓬榄种源的遗传多样性高于加蓬种群。基于分子方差分析（Analysis of Molecular Variance, AMOVA）的方差计算得到的两两phiPT值可有效区分温博勒榄与加蓬榄。基于贝叶斯算法、判别主成分分析（Discriminant Analysis of Principal Components, DAPC）以及非加权组平均法（Unweighted Pair Group Method with Arithmetic Mean, UPGMA）的种群结构与聚类分析结果显示，喀麦隆是尼日利亚与加蓬的加蓬榄种质资源分布的核心区域。加蓬种质倾向于与尼日利亚种质聚为独立类群，而温博勒榄则与加蓬榄形成了显著区分的聚类分支。本研究证实，SilicoDArT标记适用于榄属种质的种群结构与遗传分化分析，可为未来开展种质资源补充采集以丰富基因库种质多样性，以及为驯化育种项目提供科学指导依据。

搜集汇总

背景与挑战

背景概述

该数据集基于DArTseq生成的SilicoDArT标记，分析了来自尼日利亚、喀麦隆和加蓬的Irvingia gabonensis和Irvingia wombolu树种的遗传多样性与种群结构。研究发现种群间遗传分化较高，整体遗传多样性较低，其中喀麦隆和尼日利亚的I. gabonensis种群更具多样性，且种群结构分析有效区分了两种物种。这些结果有助于指导基因库保护和驯化材料的补充，以应对森林减少和过度采收带来的威胁。