Comparative Transcriptomics Analyses across Species, Organs, and Developmental Stages Reveal Functionally Constrained...

Area of Science:

• Genomics
• Developmental Biology
• Evolutionary Biology

Background:

• The function of long noncoding RNAs (lncRNAs) is debated, with many thought to be nonfunctional due to weak selective pressures.
• While some lncRNAs have demonstrated key biological roles, particularly in gene regulation during development, their overall abundance and function across different life stages and organs remain unclear.

Purpose of the Study:

• To investigate the hypothesis that functional lncRNAs are more abundant during embryonic development compared to adult organs.
• To analyze lncRNA expression patterns across different developmental stages, organs, and species to identify conserved and potentially functional loci.

Main Methods:

• A multidimensional comparative transcriptomics analysis was performed.
• Data included five developmental time points (embryonic, newborn, adult, aged), four organs (brain, kidney, liver, testes), and three species (mouse, rat, chicken).

Main Results:

• lncRNAs were overwhelmingly preferentially expressed in adult and aged testes, suggesting permissive transcription during spermatogenesis.
• lncRNAs were less abundant in embryos and newborns, with differential expression patterns conserved between mouse and rat.
• lncRNAs expressed in somatic organs and during development exhibited higher evolutionary conservation, especially in promoter regions.

Conclusions:

• Functionally constrained lncRNA loci are enriched in developing organs.
• The findings suggest that many functional lncRNAs may operate in an RNA-independent manner, challenging traditional views of lncRNA function.