PHYLOGENETIC ANALYSIS OF ASPERGILLUS FLAVUS POPULATIONS IN MEXICO, TEXAS, AND PAKISTAN

Abstract

Aflatoxins are carcinogenic secondary metabolites that are produced mainly by members of the Aspergillus section Flavi species. Maize has long been associated with A. flavus, for maize seems to be especially prone to A. flavus infection.. Through simple-sequence repeat (SSR) data, it can be shown that the population of L-morphotype A. flavus in Mexico is not extremely diverse, with most individuals sharing many alleles across 17 loci of the A. flavus genome. However, in Pakistan, a country that has only had maize for a couple of centuries, the L-morphotype A. flavus community is diverse and possesses many unique alleles. For this reason, we are able to sort fungal individuals into two populations: a Modern Population (Population M) and an Ancient Population (Population A). This study shows that the diversity among the A. flavus community in Pakistan is the result of a native A. flavus population taking control of a new maize crop rather than a quick evolution of the A. flavus already present on the maize. This study will also show that the Ancient Population is older than the Modern Population through diversity measures and SplitsTree analysis.