Comparative genomic analysis identifies small open reading frames (sORFs) with peptide-encoding features in avian 16S...

Area of Science:

• * Genomics
• * Molecular Biology
• * Evolutionary Biology

Background:

• * Mammalian mitochondrial genomes (mt-DNA) are known to contain functional small open reading frames (sORFs) within ribosomal DNAs.
• * Previous research has expanded the known functional repertoire of mt-DNA beyond protein-coding genes.

Purpose of the Study:

• * To investigate the presence and conservation of putatively functional sORFs in avian mitochondrial genomes.
• * To compare avian sORFs with those identified in other vertebrates, particularly mammals.

Main Methods:

• * Comparative genomic analyses of available avian mt-DNA sequences.
• * Sequence alignment to identify conserved regions and assess polymorphism rates.
• * In-frame start/stop codon analysis and amino-acid sequence conservation evaluation.

Main Results:

• * Four highly conserved putative sORFs were identified within avian mt-DNA ribosomal DNA regions.
• * These sORFs exhibited low insertion/deletion polymorphism (<0.1%) and preserved start/stop codons in over 80% of species.
• * Avian sORFs included homologs of human peptides and two novel sequences, with conserved amino-acid sequences similar to known mt-DNA-encoded proteins.

Conclusions:

• * Avian mitochondrial ribosomal DNA harbors conserved sORFs with the potential to encode small bioactive peptides.
• * These findings suggest that the functional capacity of avian mitochondrial genomes may be underestimated.
• * The study extends the understanding of sORF encoding in mitochondrial genomes across vertebrate classes.