| Is horizontal gene transfer [1] the right term for this phenomenon? This is "incomplete lineage sorting". There's no need to invoke anything more exotic than

| Is horizontal gene transfer [1] the right term for this phenomenon? This is "incomplete lineage sorting". There's no need to invoke anything more exotic than standard vertical inheritance, but the existence of genetic diversity within populations after they split/speciate (i.e. it's not a single Adam & Eve that give rise to a new species) produces counter-intuitive patterns of relatedness like this.