Adaptive introgression in hybrid swarms between wild and domesticated barley in Israel

植物驯化在系统发育的时间尺度上是最近才发生的。因此，农作物通常与它们的野生祖先是互作的。在野生植物和驯化植物共存的地区，杂交可能发生。如果作物-野生基因流-在任何一个方向-赋予健身的好处，它可以产生杂交群体，港口，例如，在野生背景有益等位基因捐赠的作物渐渗。大麦（Hordeum vulgare L.）是一种重要的作物物种，其驯化过程已在考古学，遗传学和分子水平上进行了深入研究。在过去的几十年里，植物学家已经观察到“六棱野生大麦”，即野生大麦每个花序节显示三个可育小花，这是驯化大麦的标志性特征。产生这些中间形式有几种途径：（i）野生和驯化类型之间的杂交;（ii）驯化基因的从头突变;（iii）通过基因重组的去驯化。我们的初步序列数据在以色列的三个六行野生大麦种群的支持存在的杂合群体显示驯化的单倍型，否则野生的基因组背景，并激发适应性渗入的假设驯化的六行穗（Vrs 1）等位基因到杂草野生大麦。为了验证这一假设，我们将进行以下实验和分析：（i）从以色列新收集的六棱野生大麦和同域二棱基因型的群体基因组分析，以检测作物-野生基因流的基因组足迹;（ii）生态生理实验，以了解杂草大麦六棱表型的适合度结果;以及（iii）在实验种群中绘制与杂草性相关的性状的遗传图谱，以确定涉及野生植物适应农业环境的遗传因素。利用一个经过充分研究的适合遗传研究的植物驯化模型，我们的研究将揭示帮助野生植物在人造栖息地中茁壮成长的适应过程。

Plant domestication has occurred very recently on a phylogenetic timescale. Hence, crop plants are often interfertile with their wild progenitors. In regions, where wild and domesticated plants co-occur, hybridization can happen. If crop-wild geneflow – in either direction – confers fitness benefits, it can give rise to hybrid swarms that harbor, for instance, in a wild background beneficial alleles donated from a crop introgressor. Barley (Hordeum vulgare L.) is an important crop species, whose domestication process has been intensely studied at the archaeological, genetic and molecular level. In past decades, botanists have observed “six-rowed wild barley”, i.e. wild-growing barley showing three fertile florets per inflorescence node, a hallmark trait of domesticated barley. There are several avenues to bring about these intermediate forms: (i) hybridization between wild and domesticated types; (ii) de novo mutation of domestication genes; (iii) de-domestication by genetic recombination. Our preliminary sequence data of three six-rowed wild barley populations in Israel support the presence of hybrid swarms showing domesticated haplotypes in an otherwise wild genomic background, and motivate the hypothesis of adaptive introgression of domesticated SIX ROWED SPIKE (Vrs1) alleles into weedy wild barley. To test this hypothesis, we will conduct the following experiments and analyses: (i) population genomic analyses of newly collected six-rowed wild barleys from Israel and sympatric two-rowed genotypes to detect genomic footprints of crop-wild gene-flow; (ii) eco-physiological experiments to understand the fitness consequence of a six-rowed phenotype in weedy barley; and (iii) genetic mapping of traits associated with weediness in experimental populations to identify genetic factors involved in adaptation of wild plants to agricultural environment. Taking advantage of a well-studied model of plant domestication amenable to genetic studies, our research will shed light on adaptation processes that help wild plants thrive in man-made habitats.