Complex sentence: The Romanies have been described as "a conglomerate of genetically isolated founder populations", while a number of common Mendelian disorders among Romanies from all over Europe indicates "a common origin and founder effect".
Split into simpler sentences: The Romanies have been described as "a conglomerate of genetically isolated founder populations". The number of common Mendelian disorders found among Romanies from all over Europe indicates "a common origin and founder effect".