Simone Czarnobai
Doutorado | 4° ano
czarnobaisimone@gmail.com
Orientador
Orientador
Sabrina B. L. Araujo
Coorientador
Coorientador
Walter A. P. Boeger
Do intermittent barriers favor speciation?
Do intermittent barriers favor speciation?
Generally, barriers act by preventing migration and gene flow, leading to an increased probability of speciation and extinction. But the barriers are not always permanent. Considering an allopatric speciation process, the cyclic formation and breakdown of barriers, like those caused by sea-level oscillations, can only favor speciation if the isolation period is greater enough to cause differentiation between the isolated populations. Moreover, the size of the population is closely linked to the isolation time needed for speciation to occur. However, barriers are rarely impermeable, allowing migration that may vary over time. Thus, the objectives of this work were: (1) To investigate the effect of different, but constant over time, migration rate on speciation in populations; (2) To investigate the effect of an oscillatory intermittent barriers on speciation in populations; and (3) To investigate the effect of population size under the scenarios (1) and (2). We propose a genetic model of a population living in two sites. The individuals can migrate between the sites following a migration rate. Our results show that our question, launched in the title, has not a trivial answer; intermittent barriers may favor speciation but it depends on the migration intensity and its variation over time and also on population size. Besides that, these dependencies are not monotonic; there are critical values of migration rate, population size, and period that favors speciation. Our results are reinforced by empirical investigations that have found diversification in plants, fishes, bats and parasites which appears to have been closely linked to sea-level fluctuation and support the taxon pulse hypothesis.