lethal equivalent

le·thal e·quiv·a·lent

1. a combination of selective effects that on average have the same impact on the composition of the gene pool as one death; for example, two carriers at 50% risk of dying would be the lethal equivalent of one carrier at 100% risk;
2. in the population genetics of recessive traits, lethal equivalent is expressed as twice the sum of the expected number of deaths ascribable to the genetic load.
3. expression used of the genetic load of recessive genes in heterozygous state that if in homozygous state would cause death or carry a risk of death. The expected number of deaths from all such genes is expressed in lethal equivalent.

lethal equivalent

Etymology: L, letum, death, aequus, equal, valere, to be strong
a recessive allele carried in the heterozygous state that would be lethal in the homozygous state, or any combination of alleles, each with slightly deleterious effects, that are equivalent to such an allele. It is estimated that a person carries an average of three to eight lethal equivalents. See also lethal allele.

le·thal equiv·a·lent

(lēthăl ē-kwivă-lĕnt)
1. Combination of selective effects that on average have the same impact on the composition of the gene pool as one death.
2. In the population genetics of recessive traits, lethal equivalent is expressed as twice the sum of the expected number of deaths ascribable to the genetic load.
3. Expression used of the genetic load of recessive genes in heterozygous state that if in homozygous state would cause death or carry a risk of death. The expected number of deaths from all such genes is expressed in lethal equivalent.
References in periodicals archive ?
69) was very close to the sum of the two separate lethal equivalent estimates (1.
Their method allows for an easy comparison of the costs of inbreeding across studies and is based on the concept of lethal equivalents, which is the number of deleterious genes whose cumulative effect is the equivalent of one lethal.
Estimates of the number of lethal equivalents were obtained using the regression equation:
Hence, the lower limit for the number of lethal equivalents per gamete is given by B, whereas the upper limit is (A + B).
To be able to assess the total effects of inbreeding on survival, I also estimated lethal equivalents for overall survival from egg to breeding age.
Since the estimates of lethal equivalents are per gamete, the average song sparrow egg on Mandarte Island carried an estimated minimum of 2B = 5.
1956), a lethal equivalent is a group of genes that would on average cause one death if dispersed in different individuals and made homozygous.
However, the lethal equivalent numbers based on Sorensen's method were not underestimates due to the use of open-pollinated progeny rather than cross-pollinated progeny.
We estimated the numbers of embryonic lethal equivalents in two ways.
The number of lethal equivalents per zygote can be estimated as 2B = -4 ln(R).
The numbers of lethal equivalents of the total sample and different areas were expressed as population estimates, in which the lethal numbers were estimated from mean percentages of empty seeds of the areas.
In wind-pollinated conifers, primary selfing rates commonly are intermediate and the embryonic lethal load is often quite high, on the order of 10 recessive lethal equivalents per genome on average (Sorensen 1969; Bishir and Namkoong 1987), compared with only a few recessive lethal equivalents on average in most out-crossing plant or animal species (Crumpacker 1967; Dobzhansky 1970, ch.