The Annals of Applied Probability
- Ann. Appl. Probab.
- Volume 19, Number 1 (2009), 15-48.
Degenerate diffusions arising from gene duplication models
We consider two processes that have been used to study gene duplication, Watterson’s [Genetics 105 (1983) 745–766] double recessive null model and Lynch and Force’s [Genetics 154 (2000) 459–473] subfunctionalization model. Though the state spaces of these diffusions are two and six-dimensional, respectively, we show in each case that the diffusion stays close to a curve. Using ideas of Katzenberger [Ann. Probab. 19 (1991) 1587–1628] we show that one-dimensional projections converge to diffusion processes, and we obtain asymptotics for the time to loss of one gene copy. As a corollary we find that the probability of subfunctionalization decreases exponentially fast as the population size increases. This rigorously confirms a result Ward and Durrett [Theor. Pop. Biol. 66 (2004) 93–100] found by simulation that the likelihood of subfunctionalization for gene duplicates decays exponentially fast as the population size increases.
Ann. Appl. Probab., Volume 19, Number 1 (2009), 15-48.
First available in Project Euclid: 20 February 2009
Permanent link to this document
Digital Object Identifier
Mathematical Reviews number (MathSciNet)
Zentralblatt MATH identifier
Primary: 60J60: Diffusion processes [See also 58J65] 60J70: Applications of Brownian motions and diffusion theory (population genetics, absorption problems, etc.) [See also 92Dxx] 92D15: Problems related to evolution 92D20: Protein sequences, DNA sequences
Durrett, Rick; Popovic, Lea. Degenerate diffusions arising from gene duplication models. Ann. Appl. Probab. 19 (2009), no. 1, 15--48. doi:10.1214/08-AAP530. https://projecteuclid.org/euclid.aoap/1235140331