MacLellan, or variants thereof, is a surname of Scottish or Irish origin. The surname is an Anglicization of the Scottish Gaelic Mac Gille Fhaolain and the Irish Gaelic Mac Giolla Fhaoláin which means "son of the servant of (Saint) Faolán". The personal name, Faolán, is thought to be a diminutive of faol, meaning "wolf" or "little wolf".
The primary goal of the MacLellan DNA Project is to find the common surname progenitor for each YDNA cluster of men who carry a version of the Mac Gille Fhaolain surname. YDNA surname projects like this, allow us to build a phylogenetic tree of men's direct paternal lineage since the Y-chromosome is passed down from father to son completely intact without any DNA contributed from the mother. Each time there is a mutation on the Y-chromosome it will be passed down to every generation of males that follows. We can use these mutations to build a tree and see which MacLellans share a surname progenitor. We can even find DNA mutation branches within the various MacLellan trees. YDNA also allows us to see other surnames that MacLellans branch from in order to help build a more comprehensive picture of common origins.
A secondary goal is to find the Chieftain line of Clan MacLellan. The easiest way to determine this would be to find MacLellans that can trace their lineage to the chieftain line and compare their YDNA. We can also try to age the various MacLellan YDNA clusters by using Genetic Distance( the number of mutations ) to see if they line up with the origins of Clan MacLellan. We can also look for surnames that historians have associated as having common origins with Clan MacLellan, such as MacMillan, McGillis, Cannon, or Lenny and see if they share common YDNA.
A third goal is to provide a place for people of any surname to compare their autosomal "mixed" DNA with those that have MacLellan ancestors. This can be done by taking the Family Finder test which will find 5 generations of relatives.
http://www.dgnhas.org.uk/transonline/SerIII-Vol59.pdf ( start at page 49 )