Instituto Agronomico

**Allometric genetics X. A three point test involving a gametophyte
gene ( Ga10 A2 Bt)**

--Luiz Eugenio Coelho de Miranda and Luiz Torres de Miranda

In MNL 64:34-35, using data reported by J. Gonella, J and P. A. Peterson,
PA with two kinds of families of backcrosses in the presence and absence
of *Ga10*, we have developed a solution for the problem. In the present
report a solution is presented for the case of having only one kind of
family, that is, two marker factors segregating in the presence of the
gametophyte factor. The original data from the authors cited are in the
presence of the gametophyte factor: *A2 Bt* = 378, *A2 bt* =
7, *a2 Bt* = 117, and *a2 bt* = 253.

We have shown by allometric genetics that the calculus of the recombination of the markers is straightforward.

So the distance q between *A2* and *Bt* is directly obtained
as (*A2 bt* + *a2 Bt*)/n.

With the values presented we have the sum total of *A2* = 385,
*a2*
= 2,270, *Bt* = 495 and *bt* = 2,160. With these values the expectations
by the proposed solution are as presented in Table 1, together with the
algebraic and numeric calculations.

Table
1. Data as presented by P. A. Peterson and J. Gonella in MNL 49:71-73
in their Table 1. The expectations of the segregation as presented by L.
T. de Miranda and L. E. C. de Miranda in MNL 64:34-35 and subsequent algebraic
steps. p is the recombination *Ga10 A2*, and q those of *A2 Bt*.
a is the allometric coefficient of *Ga10*.

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