Table 2. Probabilities of F1 and backcross hybrids carrying the observed hybrid genotype.

All six hybrids carried genotype (LA)(A/G)(A/C)(CAG/TGC)(C/T)(A/C); frequencies of the diagnostic SNPs are given in Table 1. The fixed mitochondrial differences render some parental combinations impossible. The shared polymorphism at dSNP 2 makes it possible that the observed hybrid genotype derives from backcrossing, albeit at very low probabilities (<0.05).

F1 genotype
F1 combinations	mtDNA	Probability
LA f × BF m	LA (1.0)	0.90
LA m × BF f	BF (1.0)	0.00*
Backcross genotype
Backcross combinations	mtDNA	Probability
F1 f × BF m	LA (1.0)	0.028
F1 f × LA m	LA (1.0)	0.034
F1 m × LA f	LA (1.0)	0.034
F1 m × BF f	BF (1.0)	0.00*

Notes.

^*Probability is 0 due to the absence of BF mitochondrial haplotype in the observed hybrid genotype.

LA

Laysan Albatross

BF

Black-footed Albatross

f

female

m

male