First of all you have provided no cite that Beta Israel are genetically the same so that would be OR unless you can  Secondly even if you did have a source it would be disputed  contested because neither tribes recognises that they are genetically the same  Secondly Amhara is not a genetic affiliation  The are several unrelated tribes who all adopted the same language and religion ie  Ethiopian Orthodox  Any tribes like the Beta Israel who have their own language are not Amhara the word Amhara in Ethiopia is virtually synonymous with Orthodox of course not entirely since there are also Orthodox non Amharas thise who speak other languages  Even the so called Muslim AMharas are not regarded as fully Amhara but go by a different name  All of this is sourced try reading The Ethiopians also Wax and Gold