Acomys, the closest relatives to Gerbils, do express Pdx-1 protein and have similar islet morphology to Gerbils

The Comparative Anatomy of Islets

“…A recent study of the tammar wallaby, Macropus eugenii, showed that ghrelin cells were found in the developing pancreas up to day 10 but were not present 150 days after birth (Menzies et al 2009). These data are the same as found in mice (Heller et al 2005;Heller 2009). …”

Model systems for regeneration: the spiny mouse, Acomys cahirinus

“…There are at least 88 such antibodies reported and ELISAs have also been used to detect cytokines, thus there appears to be little problem of cross-reactivity with these antibodies, and where protein homology has been compared between Acomys, Mus and human The last row shows those antibodies that are commonly used for Mus, but have failed to identify immune cell types in Acomys using flow cytometry. Data from: Bellofiore et al, 2017;Brant et al, 2015Brant et al, , 2016Brant et al, , 2019Castel and Hockman, 1978;Gawriluk et al, 2016Gawriluk et al, , 2019Gustavsen et al, 2009;Hułas-Stasiak and Gawron, 2007Hutton et al, 2009a,b;Jiang et al, 2019;Maden 2018;Maden et al, 2018;Matias Santos et al, 2016;Montandon et al, 2014;Okamura et al, 2018 it is expectedly high (Gawriluk et al, 2019 preprint). In contradiction, however, very few antibodies used for Mus T cell analysis by flow cytometry cross-react with Acomys (Gawriluk et al, 2019 preprint;Pennello et al, 2006), suggesting that an investment in antibody production in this area of research would be highly beneficial.…”