Hybrid species formation in Brassica

新物种通常通过杂交进化，即两个物种走到一起，形成一个拥有来自两个亲本物种的遗传信息的新物种。众所周知，这一过程现在非常普遍，特别是在开花植物中，这是我们许多农业上重要的粮食作物的原因。杂交或多基因组(多倍体)物种的例子包括小麦、马铃薯、甘蔗、香蕉和油菜籽。杂交植物必须处理两组相互竞争的遗传信息。在有性繁殖过程中，必须严格控制减数分裂，以产生稳定的、可育的后代，这是杂交建立为新物种的必要条件。然而，当一个细胞中存在两组不同的、潜在干扰的染色体时，控制减数分裂可能是有问题的。由于杂交物种在野外非常常见，植物在野外自然会稳定下来。然而，人类制造合成杂交种的尝试往往不成功，而且我们对杂交种稳定背后的机制的理解很差。Brassica属包括许多重要的作物，如油菜、西兰花、甘蓝和芥菜，为探索杂交物种的形成提供了一个很好的模式。例如，由油菜(B.napus)组成的物种是含有我们栽培的卷心菜(B.oleracea)的物种和含有栽培的萝卜(B.Rapa)的物种之间的进化杂交。通过研究杂交物种的形成，我希望弄清楚如何利用这些自然进化过程在甘蓝属中为人类农业造福。杂交和基因组加倍是经常导致活力增加和利用自然界不同环境生态位的能力增强的过程。因此，如果我们能够利用这些过程产生新的杂交物种，这些物种可能会对高温、干旱和疾病等环境条件有更广泛的耐受性，从而维持农业生产。

New species often evolve through hybridisation, i.e. two species coming together to form a new species with genetic information from both parent species. This process is now known to be very common, particularly in the flowering plants, and is responsible for many of our agriculturally significant food crops. Examples of hybrid or many-genome (polyploid) species include wheat, potato, sugarcane, banana and canola.Hybrid plants have to deal with two competing sets of genetic information. During sexual reproduction, meiosis must be tightly controlled in order to produce stable, fertile progeny, which is a requirement for a hybrid to establish as a new species. However, controlling meiosis when two different, potentially interfering sets of chromosomes are present in one cell can be problematic. Plants naturally stabilise on their own in the wild, as hybrid species are extraordinarily common. However, human attempts to make synthetic hybrids are often unsuccessful, and our understanding of the mechanisms behind hybrid stabilisation is poor. The Brassica genus, which includes many important crops such as oilseed rape, broccoli, cabbage and mustards, provides an excellent model with which to explore hybrid species formation. For example, the species which comprises oilseed rape (B. napus) is an evolutionary hybrid between the species containing our cultivated cabbages (B. oleracea) and the species containing cultivated turnip (B. rapa).By investigating how hybrid species form, I hope to work out how to utilise these natural evolutionary processes for human agricultural benefit in the Brassica genus. Hybridisation and genome doubling are processes which often result in increased vigour and ability to exploit different environmental niches in nature. Hence, if we can harness these processes to produce new hybrid species, such species may have a wider tolerance of environmental conditions such as heat, drought and disease, sustaining agricultural production.