It has been shown [ 14] that for a two-way cross and ignoring selection, the allele substitution effects for QTL or markers in one parental breed depend on the allele frequencies in the other parental breed.
In fact with overdominance, allele substitution effects may have opposite signs in the parental breeds, depending on allele frequencies in the two breeds.
Indeed, there was a variation in the incidence of pigs with clinical signs resembling PMWS within breeds depending on the herd of origin [ 37].
When overdominance is present, the allele substitution effect α = a + (1 - 2 p) d may have opposite signs in the parental breeds, depending on allele frequencies p in the two breeds [ 12].
The 'best' breeds depend on what you want from them.
The Pew Initiative study points out that the impact of escaped aquaculture fish, whether transgenic or conventionally bred, depends on their "net fitness" compared with wild species.
It is assumed that the genetic structure of a livestock breed depends mostly on gene flow due to exchanges between herds.
β is the vector of fixed factors which included: farm, breed effects, and depending on the analysis, also included either the percentage of infection and/or ADG.
That being said, sometimes being consistently dateless can stir its own breed of gossip, depending on the context--a famous celebrity going solo is understandable; a political figure probably wouldn't be.
