Medea selfish genetic elements as tools for altering traits of wild populations: a theoretical analysis.
One strategy for controlling transmission of insect-borne disease involves replacing the native insect population with transgenic animals unable to transmit disease. Population replacement requires a drive mechanism to ensure the rapid spread of linked transgenes, the presence of which may result in a fitness cost to carriers. Medea selfish genetic elements have the feature that when present in a female, only offspring that inherit the element survive, a behavior that can lead to spread. Here, we derive equations that describe the conditions under which Medea elements with a fitness cost will spread, and the equilibrium allele frequencies are achieved. Of particular importance, we show that whenever Medea spreads, the non-Medea genotype is driven out of the population, and we estimate the number of generations required to achieve this goal for Medea elements with different fitness costs and male-only introduction frequencies. Finally, we characterize two contexts in which Medea elements with fitness costs drive the non-Medea allele from the population: an autosomal element in which not all Medea-bearing progeny of a Medea-bearing mother survive, and an X-linked element in species in which X/Y individuals are male. Our results suggest that Medea elements can drive population replacement under a wide range of conditions.
Division of Biology, MC156-29, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA.
Catherine M
CM
Ward
Jessica T
JT
Su
Yunxin
Y
Huang
Alun L
AL
Lloyd
Fred
F
Gould
Bruce A
BA
Hay
D000818:Animals; D009033:Culicidae / Q000235:genetics*; D018562:Disease Transmission, Infectious / Q000517:prevention & control*; D005260:Female; D005298:Fertility / Q000235:genetics; D056084:Genetic Fitness / Q000235:genetics; D005828:Genetics, Population; D005838:Genotype; D007303:Insect Vectors / Q000235:genetics*; D008297:Male; D008957:Models, Genetic; D012091:Repetitive Sequences, Nucleic Acid / Q000235:genetics*; D019076:Transgenes / Q000235:genetics*