# Transcriptomic Analysis Provides Molecular Insights into Skin Development in Dezhou Donkey Foals

## TL;DR

This study reveals how skin development in Dezhou donkey foals changes at the molecular level from birth to one year of age.

## Contribution

The study provides new insights into the transcriptomic changes during skin maturation in donkey foals.

## Key findings

- Skin development transitions from structural formation to maintenance by one year of age.
- Barrier-related genes and hair follicle pathways are up-regulated in yearling donkeys.
- Collagen synthesis genes are down-regulated, indicating reduced tissue construction activity.

## Abstract

This study characterized molecular changes during early postnatal skin development in Dezhou donkeys by comparing transcriptomic profiles between newborn and yearling foals. RNA sequencing of skin samples from 13 animals revealed extensive gene expression remodeling during the first year of life, with predominant down-regulation of genes associated with rapid tissue construction and matrix deposition. The molecular signature indicated a developmental transition from active structural formation to maintenance-focused homeostasis. Enhanced expression of barrier-related genes and hair follicle development pathways in yearlings suggests continued skin maturation well beyond birth. These findings provide molecular insights into age-dependent skin characteristics that could inform management practices and quality assessment strategies in donkey production systems.

Skin development undergoes significant molecular changes during early life stages in mammals. This study investigated transcriptomic differences in skin tissues between newborn (Y0) and one-year-old (Y1) Dezhou donkey foals using RNA-sequencing technology. Skin samples were collected from 13 Dezhou donkeys (7 newborns and 6 one-year-olds) and subjected to transcriptome analysis using the Illumina NovaSeq 6000 platform. A total of 133.66 Gb of clean data was obtained, yielding 252,342 transcripts and 204,683 unigenes. Differential expression analysis revealed 9878 significantly differentially expressed genes (DEGs) between age groups, with 4252 up-regulated and 5626 down-regulated genes in Y1 compared to Y0. Functional enrichment analysis identified key pathways, including ECM–receptor interaction, PI3K-Akt signaling, WNT signaling, and TGF-β signaling pathways. Notable findings included up-regulation of keratin genes (KRT1) and WNT family genes (WNT3, WNT4, WNT5, WNT6, WNT7, WNT10) in one-year-old foals, while collagen genes (COL1A, COL4A, COL5AS) and TGF-β signaling components (TGFB2, TGFB3, BMP5) were down-regulated. These results suggest that skin maturation involves enhanced barrier function, hair follicle development, and reduced collagen synthesis rates, providing insights into mammalian skin development mechanisms and potential applications in veterinary medicine and comparative biology.