The Lundahl sequence factor is a mathematical means of measuring and defining genetic differences and similarities across a variety of species. Although it was originally used to track possibly-invasive species that may have originated from planets different from their present habitat through accidental or undocumented introduction, it is most well-known for its use in defining a mathematical value of how different a species must be from another to be defined as a distinct Kin as opposed to a subspecies of an extant Kin.
The formulae used to derive a Lundahl factor have changed and been modified throughout the years since the introduction of the concept towards the start of the Millennial Calm around 3097 CGC. Groups focused on genetics — most prominently, Adessi Biosciences — will do independent reviews of existing genetic knowledge and Lundahl-related equations every five to ten years, and such reviews tend to place focus on new advancements in genetics and related fields and how they match, or do not match, existing Lundahl sequence models. Because of these reviews taking time on their own and coming from groups of varying power and reach throughout the Ealdremen system, some governments or other powers basing policy off of Lundahl sequence factor values may use different parameters or versions of the Lundahl sequence factor from one another, and there have been historical controversies when major genetic reviews do not agree with one another, particularly when this disagreement occurs across major political divides.
Most notably, the Lundahl sequence factor is one of several reasons why hybrids of different Kin species are not considered separate political entities from their parent species, and it was also used as rationale for the robotic sabarús alphas' political status shifting from Kin to Unkinned in 4342 CGC.