Noirot Michel, Charrier A., Stoffelen P., Anthony François. (2016). Reproductive isolation, gene flow and speciation in the former Coffea subgenus : a review. Trees : Structure and Function, 30 (3), p. 597-608. ISSN 0931-1890.
Titre du document
Reproductive isolation, gene flow and speciation in the former Coffea subgenus : a review
Noirot Michel, Charrier A., Stoffelen P., Anthony François
Source
Trees : Structure and Function, 2016,
30 (3), p. 597-608 ISSN 0931-1890
The former Coffea subgenus is a species complex showing qualitative gene flow and reproductive barriers between species. Such qualitative gene flow allowed its evolution over time, particularly during the successive forest expansion-regression cycles in relation with glaciation periods. The present paper reviews the main botanical, geographical and genetic characteristics of the Coffea genus and then focuses on the former Coffea subgenus. Its broad distribution in Africa, Madagascar and Mascarene Islands is related to the high diversity of ecological situations. The importance of sympatry and parapatry cases and their role on gene flow possibilities between species is then underlined in the paper. Such gene flow is nevertheless partially limited by reproductive barriers: flowering date, frequency of hybrid F1 emergence, as well as the vigor and fertility of such hybrids. When hybridization occurs, distortion of segregation and disruptive selection would allow qualitative flow of non-adaptative genes, thus limiting the effect of genetic drift in small populations. The last part of the paper defines the notion of metaspecies in the case of the former Coffea by extension of the concept of metapopulation to species. The evolution over time of a metaspecies is finally discussed in relation with sympatry situations, gene flow possibilities and forest fragmentation.
