Genetics underlying inbreeding depression in Mimulus with contrasting mating systems

摘要: The importance of inbreeding depression in theoretical considerations mating-system evolution1,2,3,4,5 and its potential impact on the persistence small populations6 has renewed interest genetic basis this phenomenon. Inbreeding increases homozygosity. This can produce for two different reasons: first, deleterious recessive or partially alleles that are masked at heterozygous loci by dominant become fully expressed homozygotes; second, may interact an overdominant manner, such fitness either type homozygote is lower than heterozygotes. These mechanisms long-term effects populations experiencing increased levels inbreeding. resulting from be removed selection, but produced overdominance cannot without lowering mean population1,2,3,4,5. Using a North Carolina 3 breeding programme7, most powerful quantitative genetics technique available8,9,10, we show here mainly responsible closely related annual plants, primarily selfing Mimulus micranthus mixed-mating M. guttatus. Estimates indicate more nearly additive they