5'-Transducing SVA retrotransposon groups spread efficiently throughout the human genome.

Area of Science:

• Genomics
• Molecular Biology
• Evolutionary Biology

Background:

• SVA elements are the youngest family of hominid non-LTR retrotransposons.
• They are composite repetitive elements that continuously alter the human genome.
• Understanding their assembly and transcriptional regulation is crucial for studying genome evolution.

Purpose of the Study:

• To investigate the structural diversity of SVA elements.
• To elucidate the mechanisms of SVA element assembly and transcriptional regulation.
• To identify novel SVA variants and their contribution to genomic rearrangements.

Main Methods:

• Analysis of 116 SVA elements on human chromosome 19.
• Classification of SVA elements into structural variants.
• Genome-wide inventory of 5'-transduced SVA elements.
• Detailed analysis of a human-specific SVA 5' transduction group.

Main Results:

• Seven structural variants of SVA elements were identified, including 3'-truncated and 5'-transduced elements.
• A genome-wide inventory revealed that 5'-transduced SVA elements constitute approximately 8% of all human SVA elements.
• Evidence suggests SVA elements can acquire 5' promoter sequences, leading to transcriptional control by external promoters.
• SVA-mediated 5' transduction events involve alternative RNA splicing at cryptic splice sites.
• A specific human-specific SVA 5' transduction group, derived from MAST2 gene promoter, is actively transcribed.

Conclusions:

• SVA-mediated 5' transduction events generate structural diversity in SVA elements.
• These events represent a novel source of genomic rearrangements.
• SVA elements contribute significantly to the genomic diversity of hominids.