E-M78, like its parent clade E-V68, is thought to have an African origin. Based on genetic STR variance data, Cruciani et al. (2007) suggests that this subclade originated in “Northeastern Africa”, which in the study refers specifically to the region of Egypt and Libya.
Prior to Cruciani et al. (2007), Semino et al. (2004) had proposed a place of origin for E-M78 further south in East Africa. This was because of the high frequency and diversity of E-M78 lineages in the region of Ethiopia. However, Cruciani et al. (2007) were able to study more data, and concluded that the E-M78 lineages in the Horn of Africa were dominated by relatively recent branches (see E-V32 below). They concluded that the region of Egypt was the likely place of origin of E-M78 based on “the peripheral geographic distribution of the most derived subhaplogroups with respect to northeastern Africa, as well as the results of quantitative analysis of UEP and microsatellite diversity”.
Cruciani et al. (2007) also note this as evidence for “a corridor for bidirectional migrations” between Northeast Africa (Egypt and Libya in their data) on the one hand and East Africa on the other. Because Cruciani et al. (2007) also proposed that E-M35, the parent clade of E-M78, originated in East Africa during the paleolithic and subsequently spread to the region of Egypt. E-M78 in East Africa, is therefore the result of a back migration. The authors believe there were “at least 2 episodes between 23.9–17.3 ky and 18.0–5.9 ky ago”.
Another probable migration to the south from Egypt was noted by Hassan et al. (2008) based upon their survey of Sudan. Specifically E-V12 and E-V22, “might have been brought to Sudan from North Africa after the progressive desertification of the Sahara around 6,000-8,000 years ago”.
Northwards from Egypt and Libya, E-M78 migrated into the Middle East, but additionally Trombetta et al. (2011) proposed that the earlier E-V68 carrying population may have migrated by sea directly from Africa to southwestern Europe, because they observed cases of E-V68* (without the M78 mutation) only in Sardinia, and not in the Middle Eastern samples. Concerning E-M78, like other forms of E-V68 there is evidence of multiple routes of expansion out of an African homeland.
On the other hand, while there were apparently direct migrations from North Africa to Iberia and Southern Italy (of people carrying E-V68*, E-V12, E-V22, and E-V65), the majority of E-M78 lineages found in Europe belong to the E-V13 sub-clade which appears to have entered Europe at some time undeterminded from the Near East, where it apparently originated, via the Balkans.
Coming to similar conclusions as the Cruciani and Trombetta team, Battaglia et al. (2008), writing prior to the discovery of E-V68, describe Egypt as “a hub for the distribution of the various geographically localized M78-related sub-clades” and, based on archaeological data, they propose that the point of origin of E-M78 (as opposed to later dispersals from Egypt) may have been in a refugium which “existed on the border of present-day Sudan and Egypt, near Lake Nubia, until the onset of a humid phase around 8500 BC. The northward-moving rainfall belts during this period could have also spurred a rapid migration of Mesolithic foragers northwards in Africa, the Levant and ultimately onwards to Asia Minor and Europe, where they each eventually differentiated into their regionally distinctive branches”.
The division of E-V68 into sub-clades such as E-V12, E-V13, etc. has largely been the work of an Italian team including Fulvio Cruciani, Beniamino Trombetta, Rosario Scozzari and others. They started on the basis of STR studies in 2004, and then in 2006 they announced the discoveries of single nucleotide polymorphism (SNP) mutations which could define most of the main branches with better clarity, which was then discussed further in 2007. These articles were the basis of the updated phylogenies found in Karafet (2008), and ISOGG, which is in turn the basis of the phylogeny given below.