Table 1. Transmission rates of the Ts65Dn and Ms5Yah alleles observed at weaning in Ts65Dn, Ms5Yah, and Ts65Dn/Ms5Yah mice.

Original cross	Genotype	Observed number	Observed ratio	χ2	P
Ts65Dn x F1B6C3B	wt	407	66.0%	31.8	1.74×10−08
	Ts65Dn	210	34.0%
Ms5Yah x F1B6C3B	wt	85	83.3%	23.5	1.27×10−06
	Ms5Yah	17	16.7%
Ts65Dn x Ms5Yah	wt	73	39.5%	8.51	3.55×10−3
	Ts65Dn	50	27.0%	0.01	0.90
	Ms5Yah	16	8.6%	0.27	0.60
	Ts65Dn/Ms5Yah	46	24.9%	24.0	9.77×10−07

All the lines were kept on a mixed B6C3B background. Ts65Dn and Ms5Yah lines showed a reduced transmission rate of their respective allele at weaning that was related to post-natal lethality. Combination of both aneuploidies leads to a partial rescue for this lethality as shown by the ratio observed for the Ts65Dn/Ms5Yah genotype.