Yazar "Sevim, Volkan" seçeneğine göre listele

Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Yayın
    Evolutionary route to diploidy and sex
    (National Academy of Sciences, 2001-11-20) Tüzel, Erkan; Sevim, Volkan; Erzan, Ayşe
    By using a bit-string model of evolution, we find a successful route to diploidy and sex in simple organisms. Allowing the sexually reproducing diploid individuals to also perform mitosis, as they do in a haploid-diploid cycle, leads to the complete takeover of the population by sexual diploids. This mechanism is so robust that even the accidental conversion and pairing of only two diploids give rise to a sexual population.
  • Küçük Resim
    Yayın
    Strategies for the evolution of sex
    (American Physical Soc, One Physics Ellipse, 2001-12) Tüzel, Erkan; Sevim, Volkan; Erzan, Ayşe
    We find that the hypothesis made by Jan, Stauffer, and Moseley [Theory Biosci. 119, 166 (2000)] for the evolution of sex, namely, a strategy devised to escape extinction due to too many deleterious mutations, is sufficient but not necessary for the successful evolution of a steady state population of sexual individuals within a finite population. Simply allowing for a finite probability for conversion to sex in each generation also gives rise to a stable sexual population, in the presence of an upper limit on the number of deleterious mutations per individual. For large values of this probability, we find a phase transition to an intermittent, multistable regime. On the other hand, in the limit of extremely slow drive. another transition takes place to a different steady state distribution. with fewer deleterious mutations within the population.
  • Küçük Resim Yok
    Yayın
    Strategies for the evolution of sex
    (American Institute of Physics Inc., 2001-12) Tüzel, Erkan; Sevim, Volkan; Erzan, Ayşe
    The maintenance of a macroscopic sexual population is addressed. As a scenario, the mechanism of random conversion to sex, in the presence of a constant rate of mutation is examined. This scenario is very closely related to "coevolution of cell senescence and diploid sexual reproduction in unicellular organisms." In this work, a "senescence clock" ticks off a finite lifetime for each bit string. Sexual reproduction resets the senescence of clock; unless this happens after a number of generations of cloning, the offspring stop dividing and die.
  • Küçük Resim
    Yayın
    Testing a hypothesis for the evolution of sex
    (World Scientific Publishing Company, 2000-07-11) Örçal, Bora; Tüzel, Erkan; Sevim, Volkan; Jan, Naeem; Erzan, Ayşe
    An asexual set of primitive bacteria is simulated with a lit-string Penna model with a Fermi function for survival. A recent hypothesis by Jan, Stauffer, and Moseley on the evolution of sex from asexual cells as a strategy for trying to escape the effects of deleterious mutations is checked. This strategy is found to provide a successful scenario for the evolution of a stable macroscopic sexual population.