If eugenics is considered an attempt to "improve" the
genetic load of individuals by avoiding the birth of individuals with an undesirable
genetic load, or to promote the birth of individuals with a
genetic load considered favorable, then the association between genetic consultation and eugenics is obvious.
in a plant is called the
genetic load. Most deleterious alleles are
High frequent carriage of the studied polymorphic allele variant (79%) in parents (probands) of children suffering from CA confirms the fact of mutation accumulation in the observed families (a phenomenon of accumulation of
genetic load).
A major issue is what level of inbreeding depression is maintained in partially self-fertilizing populations given the purging effects of self-fertilization on
genetic load. Moreover, Campbell (1986), Holsinger (1988, 1991), and Uyenoyama and Waller (1991a,b,c) have demonstrated that population-level estimates of inbreeding depression alone are insufficient to predict whether a selfing variant can invade in a particular population.
Genetic factors such as inbreeding depression (
genetic load) may, therefore, be responsible for observed high rates of embryo abortion (Wiens et al., 1987, 1989; Charlesworth, 1989; Levin, 1989).
Segregation distortion can be explained by high
genetic load and selection against zygotes with homozygous deleterious recessive mutations (Launey & Hedgecock 2001).
Most of the genetic improvement from 1979 to 1985 occurred without a significant reduction in
genetic load (deleterious alleles) (Holland and Bingham, 1994).
Most cultured aquatic species are only partially domesticated and highly fecund and are, therefore, expected to have higher
genetic load and more severe inbreeding depression than species with lower fecundity and/or longer histories of domestication.
In particular, selection would reduce or purge the
genetic load of deleterious recessive alleles from populations that regularly inbreed, resulting in populations that had become at least partly "adapted" to inbreeding (Lande and Schemske 1985).
Most mutations are likely deleterious and recessive and constitute a substantial
genetic load on population fitness.
Inbreeding in black spruce (Picea mariana (Mill.) B.S.P.): Self fertility,
genetic load, and performance.