PHYLOGENY

the path to alcohoism:primatetree

The evolution of alcoholism amongst primates seems to rely more on just the passing of genes to offspring. Robert Dudley conducted a study which showed the relationship between the rising ethanol content in ripening fruit and the consumption of such fruit by frugivorus (fruit-eating) primates. Ethanol occurs naturally by the fermentation of yeasts and fruit sugars. This means that the riper the fruit is, the higher the concentration of alcohol will be. Consumption of such fruits containing low-concentrations of ethanol can act as a feeding stimulant, encouraging continued consumption of such fruits. Behavioral responses to ethanol may in turn have a direct effect of natural selection from frugivorous species including primates and lineages ancestral to humans. As the vervet monkeys were moved to more highly human populated environments, they were surrounded by more available alcohol in higher concentrations and higher amounts.

lasting effects:

Alcohol content makes fruit more appealing to human ancestors which in turn causes the evolution of desire for alcohol in humans. The constant comsumption of such alcoholic fruits promotes the survival the fruit species as they coevolve to follow the monkey's alcoholic interests. Fruit over time contained a higher sugar content to promote fermentation making them attractive to vervets with alcoholic tendencies. As species evolved and continued to eat ethanol-containing fruits, it is suggested that pre-existing biases toward such fruit were passed on from generation to generation [3]. This predisposition as well as the immediately stimulating feeding reward may underlie the present day patterns of alcohol consumption and abuse that can be seen beyond the monkey population.

model organisms:

Vervet monkeys amongst other Old World primates provide outstanding model organisms to observe the acquisition of human alcoholism. By examining the formation of this habit in monkeys, evolved behaviors can be extrapolated to humans as we are close ancestors relative to evolutionary time. Both humans and vervet mokeys are classified under the sub-order, Catarrhine.The heritablity of alcholosm can be analyzed in this monkey population and then applied to humans because our genome and behaviors are incredibly similar. While fermented fruit may have pushed ancestral monkeys into alcoholism, it may have been something similar which started the linegae of humans on forming a habit so degrading to their fitness.