FEATURED , Genetics , Research

Alan Stolier, MD/


Mendel and his peas - is that all there is?

Infectious Hereditary

DNA is passed from parent to offspring, a process called vertical gene transfer. 

Infectious heredity is a form of non-Mendelian dominance in which infectious genetic material particle within a host cell brings about changes in the phenotype of the host and most importantly can be passed on to progeny. That heritable material, though usually described with viruses it has also been described in bacteria. The offspring would be essentially uniparental.

Scientists have known for some time that genes are able to move from one species to another a process called horizontal gene transfer (HGT). As an example, antibiotic resistance in most instances occurs as genes move effortlessly between bacterial species. It is estimated that up to 81% of prokaryotic cells have been affected by HGT at one point.  It has only been recently that once regarded as a trait of less complicated organisms has now been found to be true in humans as well.

Crisp et al at the University of Cambridge (Crisp et al) has had the opportunity to study horizontal gene transfer in high-quality genomes in 26 non-vertebrate species (10 primates, 12 flies and four nematodes) in addition to 14 vertebrates discovered that the bacteria and eukaryotes were the most common donors in human horizontal transfer.

The authors believe that HGT is both ancient and ongoing. Horizontally acquired genes can undergo duplication and diversification. The genes concerned frequently code. 

For enzyme activities and do not appear to be conspicuously different in vertebrates and invertebrates. The authors found this surprising given the difference between the complexity of the 2 groups. 

“Although observed rates of acquisition of horizontally transferred genes in eukaryotes are generally lower than in prokaryotes, it appears that, far from being a rare occurrence, HGT has contributed to the evolution of many, perhaps all animals, and that the process is ongoing in most lineages.”

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