Table 1. Relative frequencies of induction (and therefore recombination).

TM administration	Observation	n	F	HB F
5.5 dpc	9.5 dpc	128	0.5391	0.2422
5.5 dpc	10.5 dpc	106	0.1981	0.0849
6.5 dpc	10.5 dpc	23	0.6522	0.1739
7.5 dpc	10.5 dpc	83	0.9518	0.3976
8.5 dpc	10.5 dpc	63	0.9365	0.3175

n: number of embryos.

F: total relative frequency.

HB F: frequency within the hindbrain.

Pregnant mothers were administrated with TM at different developmental stages. Embryonic development proceeds until the desired observation stage. n, number of studied embryos; F, total relative frequency (x/y) where x is the number of embryos displaying recombination events, and y the total number of embryos per experimental group; HB F, relative frequency within the hindbrain.