Biology subjects

Ehmke, E.

Publications and source records attributed to Ehmke, E..

3 recordsLinked to original sources

bioRxiv2026

A Telomere-to-telomere genome of the hibernating fat-tailed dwarf lemur (Cheirogaleus medius)

Madagascars dwarf lemurs (genus Cheirogaleus) are the only obligate-hibernating primates and closest relative to humans capable of hibernation. Endemic to the increasingly fragmented dry forests of Madagascar, the fat tailed dwarf lemur (Cheirogaleus medius) represents a unique model for understanding primate physiology and tropical hibernation. Here we present FatTail1, a highly contiguous diploid genome assembly generated from a male C. medius at the Duke Lemur Center using Oxford Nanopore Technologies PromethION sequencing. The assembly spans 2.3 Gb, with an N50 of 103Mb, L50 of 10, and a BUSCO completeness score of over 99%. In addition to a complete mitogenome, we generated allele-specific DNA methylation profiles and annotated 23,925 genes using NCBIs EGAPX. FatTail1 exceeds the gap-free contiguity of previously published strepsirrhine genomes, representing the first telomere-to-telomere genome of a Strepsirrhine primate, and providing a foundation for future studies of primate hibernation, epigenetic regulation, and conservation genomics. ARTICLE SUMMARYDwarf lemurs are the only primates and closest relative to humans capable of months-long hibernation, making them an important model for understanding metabolic adaptations with relevance to human physiology. Here we present FatTail1, the first telomere-to-telomere genome assembly of a strepsirrhine primate, generated from a fat-tailed dwarf lemur (Cheirogaleus medius) using Oxford Nanopore Technologies PromethION sequencing. In addition to a highly complete nuclear genome, we assembled the mitogenome, identified allele-specific DNA methylation profiles and annotated 23,925 genes. FatTail1 exceeds the gap-free contiguity of previously published strepsirrhine genomes and provides an improved genomic resource for studies of hibernation, comparative genomics, epigenetic regulation, evolutionary biology, and conservation of this threatened primate.

genomics↗

bioRxiv2026

Rapid centromere turnover and the adaptive radiation of lemurs

Centromeres represent essential chromosomal structures required for faithful chromosome segregation during cell division but are paradoxically hypermutable, leading to centromere drive and reproductive isolation in closely related species. Using long-read sequencing, we generate nearly complete genomes (2.1-2.5 Gbp) from eight lemur species and characterize the sequence, epigenetic and cytogenetic structure of 223 strepsirrhini centromeres providing an alternative primate perspective of centromere evolution. No lemur centromere consists of -satellite DNA that typifies the haplorhine lineage; instead, each species evolved its own distinct higher-order centromeric repeat sequence, varying substantially in both monomer length (ranging from 41-548 bp) and primary sequence composition (GC percentages 28.7-67.9%) including centromere cooption of telomeric repeats in brown lemurs. Most centromeres show characteristic hypomethylation dip regions (110-300 kbp) as candidates for kinetochore attachment. The centromere sequence motif shows no apparent sequence homology among lemur genera, even for species separated by less than 15 million years (Lemur and Eulemur). We estimate a >6-fold increased rate in primary centromeric motif turnover in strepsirrhines when compared to haplorhines and this occurred in conjunction with positive selection of the CENP-B protein in lemur lineages. We propose that lemur radiation and centromere diversification are linked, whereby accelerated motif turnover provides a stasipatric barrier contributing to rapid chromosomal evolution.

genomics↗

bioRxiv2019

A digital collection of rare and endangered lemurs and other primates from the Duke Lemur Center

Scientific study of lemurs, a group of primates found only on Madagascar, is crucial for understanding primate evolution. Unfortunately, lemurs are among the most endangered animals in the world, so there is a strong impetus to maximize as much scientific data as possible from available physical specimens. MicroCT scanning efforts at Duke University have resulted in scans of more than 100 strepsirrhine cadavers representing 18 species from the Duke Lemur Center. Scans include specimen overviews and focused, high-resolution selections of complex anatomical regions (e.g., cranium, hands, feet). Scans have been uploaded to MorphoSource, an online digital repository for 3D data. As captive (but free ranging) individuals, these specimens have a wealth of associated information that is largely unavailable for wild populations, including detailed life history data. This digital collection maximizes the information obtained from rare and endangered animals without degradation of the original specimens.

zoology↗