A new study was published recently, carried out in the Botanical Garden, and dealing with the association of spatial distribution, ecological conditions, and evolutionary genetics of the coastal endemic Iris atropurpurea.

The study was conducted by Gil Yardeni, an MSc student, supervised by Yuval Sapir, director of the Tel Aviv University Botanical Garden. It was published in Annals of Botany. The study revealed a partial reproductive isolation among populations of Iris atropurpurea: that is, crosses between different population pairs do not succeed similarly. For example, crossing plants in Netanya with pollen from Nes-Ziona did not reveal as many seeds as in a cross with pollen from the Kadima reserve. Looking at the whole distribution of Iris atropurpurea, it was found that the geographical factor, the spatial distance between populations, is not the factor affecting reproductive isolation. Rather, it was found that ecological differentiation of the habitat, and especially soil features, were associated with a reduced crossing success between populations. In addition to the conclusion regarding the role of ecology in the differentiation of populations within species, even with geographical proximity, the study also highlighted an important conservation rule: because small and fragmented populations are prone to extinction due to genetic drift and reduced genetic variation, in order to enrich the genetic pool of a population, an act called "genetic rescue", it is important to choose the source of pollen or seed enrichment carefully. This study by Gil Yardeni and her colleagues stresses the need to examine the fitness of the genetic source in order to maintain viable population dynamics.

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