This paper [1] shows they extracted the mitochondrial DNA from samples from "the UCSC Paleogenomics ab (samples AMNH 612456, OMNH 1764, AMNH 224546, OMNH 1762, AMNH 616460, Zm1, S1B1, OUMNH 1759), the University of Copenhagen (sample ZMUC AVES-105485), the McMaster University Ancient DNA Centre (samples FMNH 47395, FMNH 47396, and FMNH 47397), and Griffith University (sample D3538)".

There is also this one: https://oumnh.ox.ac.uk/learn-the-oxford-dodo

[1] https://bmcecolevol.biomedcentral.com/articles/10.1186/s1286...