Table 2. Lifespan analysis C57BL/6N×BALB/c F2 to generate interval of natural lifespan in days.

	Mean lifespan*	50% survival	7 months’ survival**	15 months’ survival**	22 months’ survival**
♂ Survival curve A	708 ±34	659	100%	85%	60%
♂ Survival curve B	812 ±34	919	100%	95%	83%
♂ Mean A&B	760 ±52	789 ±130*	100%	90 ±5%*	71 ±11%*
♀ Survival curve A	754 ±36	713	100%	92%	64%
♀ Survival curve B	851 ±38	889	100%	95%	83%
♀ Mean A&B	803 ±48	801 ±88*	100%	93 ±2%*	74 ±10%*

In Survival Curve A, euthanized animals were counted as if they had died from natural causes at the time of euthanization, and in Survival Curve B, euthanized animals were considered healthy at that timepoint. This gives the interval of natural lifespan “Mean A&B”.

*Values are mean ± SEM for Survival Curve A and Survival Curve B, and for Mean A&B variation is depicted as the span between Survival Curve A and B.

**Extrapolated from curve fit