Table 1. Admixture proportions in British Isles populations.

Admixed population	na	Proportion Scandinavian ancestry ± standard deviation	Proportion British ancestry ± standard deviation
Llangefni	80	0.10 ± 0.02	0.90 ± 0.02
Mid-Cheshire	46	0.21 ± 0.03	0.79 ± 0.03
Isle of Man	62	0.39 ± 0.04	0.61 ± 0.04
Penrith	90	0.37 ± 0.03	0.63 ± 0.03
Orkney	121	0.50 ± 0.03	0.50 ± 0.03
Shetland	63	0.41 ± 0.04	0.59 ± 0.04
Wirral ‘modern’	100	0.38 ± 0.03	0.62 ± 0.03
Wirral ‘medieval’	37	0.47 ± 0.05	0.53 ± 0.05
Wirral ‘medieval’ rarer surnames	26	0.51 ± 0.06	0.49 ± 0.06
West Lancsb ‘modern’	49	0.38 ± 0.04	0.62 ± 0.04
West Lancsb ‘medieval’	40	0.51 ± 0.04	0.49 ± 0.04
West Lancsb ‘medieval’ rarer	30	0.53 ± 0.05	0.47 ± 0.05
surnames

^asample size

^bLancashire.