Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:This is consistent with the absence of a θ-globin gene from the region between platypus α1- and ω-globin, its expected location based on its position in marsupial αglobin clusters [12,56].
Category: