Differences in gene expression help lemurs hibernate

Figure 1. Crossley's dwarf lemur

In a recent study published in Molecular Ecology, Faherty and collegues investigated the transcriptomic changes that underlie torpor in Crossley's dwarf lemurs (Cheirogaleus crossleyi; Figure 1). Researchers monitored six animals for seven months recording daily body temperature from a radio-collar equipped with a skin temperature sensor; and collected white adipose tissue (WAT) from tails using mark-recapture techniques from three distinct cycles (active, fattening, and torpor). The study was conducted in the Tsinjoarivo Classified Forest, which is one of the last remaining high-altitude forests in eastern Madagascar. During the coldest months of June and July, temperatures average 66 degrees F and can dip to 40 degrees F  - a perfect model for studying torpor!
 

Results indicate differential expression for (1) 377 genes between fattening and torpor, (2) three genes between topor and emergence, and (3) 220 genes between fattening and emergence. They generated functional annotation clusters (Figure 2) which were defined based on the widest biological significance from GO term analysis. Scientists found that during torpor dwarf lemurs experience enriched pathways for lipid biosynthes, and very high levels of expression of iron storing genes (FTH1 and FTL). 

Figure 2. Functionally enriched clusters of Crossley's dwarf lemurs during circannual cycle (Faherty et al. 2018).

This study represents the first to analyze differential expression in wild primates under entirely natural conditions. It also highlights differences in gene expression that have been found between wild and captive dwarf lemurs in regards to differential expression. Future studies on gene expression of hibernating animals or captive primates should thus interpret results with some caution. 

- Elizabeth (Liz) Tapanes
1st non-potluck