## Equations for estimation of recombination
fraction between a marker and a sporophytic lethal in F_{2}
progenies with the maximum likelihood method

**Kosterin, O.E., Berdnikov, V.A. and Gorel,
F.L. ** |
Institute of Cytology and
Genetics
Novosibirsk 630090 Russia |

If a lethal is linked to a recessive allele *a*
of a marker, then the maximum likelihood estimation p of the recombination fraction and
its standard deviation s will be determined by the following formulae:

where N is the total number of progeny, a is the number of individuals
with recessive phenotype.

If a lethal is linked to a dominant allele *A*, then the formulae become:

where N is the total number of progeny, A is the number of individuals
with dominant phenotype and a is the number of individuals with recessive phenotype.

If a lethal is linked to an allele *B* of a co-dominant marker with alleles* A*
and *B*** **then p is to be found by a numerical solution of the following
equation:

*
***2 Np**^{5}- (6A
+5H +4B)p^{4}+ 2(3A + B)p^{3}+
(5H - 4A + 2B)p^{2}- 2(H + 2B)p + 2B = 0

where N is the total number of progeny, A, B, and H are the numbers of
genotypes *A/A*, *B/B*, and *A/B*, respectively.

The standard deviation s is:

*
*