Horizontal Gene transfer (HGT)

[dwedwards]

Hi guys, this is my first post but wandering if anyone can help??!

I am studying a lot of evolution at degree level and am always confused at the theory of horizontal gene transfer and how evolutionists can distiguish this and find out which organisms certaing genes transfered from. Also how can you notice it when constructing phylogenetic trees using genes such as the SSU rRNA??

Thanks guys

[saint2006]

Detecting horizontally transferred genes can be achieved by combination of computational test. 1. GC content analysis 2. Codon usage 3. Nucleotide signatures 4. BLAST survey combined with phylogenetic analysis (comparing the gene trees with species (16S rRNA) trees).
Gene and species trees will not be congruent if the gene has been horizontally acquires in most cases. Phylogenetic discordance can help to identify HGT genes.