Atul Khajuria, Ashish Kumar | International Journal of Animal Biotechnology and Applications | Vol 12, Issue 01 | ISSN: 2455-7315
Abstract
Spermmediated gene transfer (SMGT) exploits the natural role of spermatozoa as DNA vectors to deliver exogenous genetic material to oocytes, potentially enabling economical production of transgenic large animals without complex embryo micromanipulation (1). Early proofofconcept studies established that mammalian sperm can bind, internalize, and protect exogenous DNA, leading to integration, expression, and germline transmission in various species, including pigs (24). Subsequent mechanistic work has challenged the traditional view of sperm as metabolically inert, revealing regulated DNAbinding proteins on the sperm surface and retrotransposonencoded reverse transcriptase activity that can mediate reverse transcription and nonMendelian inheritance of exogenous sequences (3). In large animal models, SMGT has achieved high apparent rates of transgenesis in pigs, with reports of up to 80% of offspring harboring an integrated transgene and more than half expressing a functional protein (19). However, concerns remain regarding integration site heterogeneity, mosaicism, variable expression, and unintended genomic effects, which are now interrogated by highresolution molecular pathology tools, including nextgeneration sequencing and epigenomic profiling. This review revisits SMGT from the vantage point of pathology and molecular pathology, critically examining biological mechanisms, factors influencing uptake and integration, optimization strategies for delivery and germline transmission in large animals, and comparative performance against zygote microinjection, viral and CRISPRbased approaches. We also discuss potential applications in xenotransplantation, agriculture, and functional genomics, and outline a framework for histopathologic, genomic, and epigenomic safety assessment of SMGTderived lines.
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