Citation Context

...ted in cases of genomic imprinting (Efstratiadis 1994). In the classical theory, classes of relatives with di¡erent maternal and paternal coe¤cients of relatedness were assigned an average coe¤cient (=-=Hamilton 1964-=-). This paper shows that the theory can easily be modi¢ed to consider maternal and paternal relatedness separately. The revised theory then speci¢es conditions under which natural selection acts di¡er...

Citation Context

...irst, some unimprinted genes have phenotypic e¡ects similar to the e¡ects of imprinted genes: for example, Igf1 (like Igf2) enhances embryonic growth in the mouse, but (unlike Igf2) is not imprinted (=-=Liu et al. 1993-=-). Second, imprinted loci appear to be clustered, with the bulk of the genome devoid of signi¢cant imprinting e¡ects (Saitoh et al. 1996; Lee et al. 1997). Such a pattern would be predicted if the evo...

Citation Context

... ¢rst is asymmetrically related on the maternal and paternal side. Maternalpaternal con£icts have previously been identi¢ed in the context of behaviours that a¡ect half-siblings (Haig & Westoby 1989; =-=Moore & Haig 1991-=-), but the theory presented in this paper generalizes to all interactions among relatives. 2 . EVOLUTIONARILY STABLE STRATEGIES The coe¤cient of relatedness of individual i to individual 0 (ri) can be...

Citation Context

...th factor 2 receptor) has the opposite pattern of expression. Paternally expressed Igf2 promotes embryonic growth, whereas maternally expressed Igf2r inhibits growth by degrading the product of Igf2 (=-=DeChiara et al. 1991-=-; Lau et al. 1996; Ludwig et al. 1996). Haig & Graham (1991) proposed that this complementary pattern of imprinting has evolved because costs imposed by an Inclusive ¢tness and genomic imprinting D. H...

Citation Context

...dividuals to whom the ¢rst is asymmetrically related on the maternal and paternal side. Maternalpaternal con£icts have previously been identi¢ed in the context of behaviours that a¡ect half-siblings (=-=Haig & Westoby 1989-=-; Moore & Haig 1991), but the theory presented in this paper generalizes to all interactions among relatives. 2 . EVOLUTIONARILY STABLE STRATEGIES The coe¤cient of relatedness of individual i to indiv...

Citation Context

...e for all possible separating strategies, unless the strategy is a symmetric ESS. At a parentally antagonistic ESS, either the maternal allele {0, x*p} or the paternal allele will be silent {x*m, 0} (=-=Haig 1996-=-; Mochizuki et al. 1996). Suppose that a pooling strategy bene¢ts patrilines at the expense of matrilines. If so, the strategy can be displaced by a separating strategy with reduced expression when ma...

Citation Context

...the mouse, but (unlike Igf2) is not imprinted (Liu et al. 1993). Second, imprinted loci appear to be clustered, with the bulk of the genome devoid of signi¢cant imprinting e¡ects (Saitoh et al. 1996; =-=Lee et al. 1997-=-). Such a pattern would be predicted if the evolution of imprinting is rare, but once one locus in a region has evolved imprinted expression, neighbouring loci can exploit the epigenetic di¡erence bet...

Citation Context

... classical theory of inclusive ¢tness implicitly assumed that a gene's expression was una¡ected by its parental origin, but this assumption is now known to be violated in cases of genomic imprinting (=-=Efstratiadis 1994-=-). In the classical theory, classes of relatives with di¡erent maternal and paternal coe¤cients of relatedness were assigned an average coe¤cient (Hamilton 1964). This paper shows that the theory can ...

Citation Context

...ch imprinting depends. The genome-wide demethylationöfollowed by remethylationöthat occurs during early mouse development erases most methylation di¡erences between maternal and paternal chromosomes (=-=Kafri et al. 1993-=-). The conditions under which natural selection would favour genome-wide suppressors of imprintingöfor that purpose, rather than as a side-e¡ect of some other functionöis a theoretical question deserv...

Citation Context

...clusive ¢tness cost when derived from the other. This terminology was chosen to emphasize the analogy to genes with sexually antagonistic e¡ects that are bene¢cial in one sex but costly in the other (=-=Rice 1987-=-). Autosomal genes spend half of their ancestry in male bodies and half in female bodies. Therefore, an allele with sexually antagonistic e¡ects will be selectively favoured if the cost to one sex is ...

Citation Context

...ossible separating strategies, unless the strategy is a symmetric ESS. At a parentally antagonistic ESS, either the maternal allele {0, x*p} or the paternal allele will be silent {x*m, 0} (Haig 1996; =-=Mochizuki et al. 1996-=-). Suppose that a pooling strategy bene¢ts patrilines at the expense of matrilines. If so, the strategy can be displaced by a separating strategy with reduced expression when maternally derived or wit...

Citation Context

...utation are likely to decrease both matrilineal and patrilineal inclusive ¢tness. Therefore, the observation that `knocking-out' maternally active Mash2 results in a failure of placental development (=-=Guillemot et al. 1995-=-) or that paternal duplications of proximal 7 result in growth-retarded mice (Cattanach et al. 1992) does not directly contradict the genetic con£ict hypothesis, as is sometimes claimed. However, such...

Citation Context

...embryonic growth in the mouse, but (unlike Igf2) is not imprinted (Liu et al. 1993). Second, imprinted loci appear to be clustered, with the bulk of the genome devoid of signi¢cant imprinting e¡ects (=-=Saitoh et al. 1996-=-; Lee et al. 1997). Such a pattern would be predicted if the evolution of imprinting is rare, but once one locus in a region has evolved imprinted expression, neighbouring loci can exploit the epigene...