why ?? there isnt a seperate law of inheritance for working terriers.Its the same for,pigeons,rats,snakes ,people etc..It also means that a dog could be a grandson of a great worker yet not be carrying any of his genes.Weve all seen people who look a ringer for 1 of their grandparents,and nothing like their own parents or other grandparents.I suppose the lesson here is only breed worker to workers and not grandchildren,nephews etc. to good workers