First, don’t do like some people I know—don’t map out a chart with sophisticated engineering software, and don’t pass it around and suggest that everyone have a look.  Autocad has been put to better uses, and uh-huh, nice stuff.

Otherwise, and while genealogical charts are useful for two or three generations of ancestors, be aware that as the list of relatives increases it becomes impossible to display as siblings, aunts, uncles and cousins, in the form of a family tree.  For this reason, the most practical method for genealogical research has come to be known as an ahnentafel (German for ancestor table).  

This refers to a genealogical numbering system for listing a person's direct ancestors in a fixed sequence of ascent. The initial subject (or the proband) of the ahnentafel is listed as 1, the subject's father as 2 and the mother as 3, the paternal grandparents as 4 and 5 and the maternal grandparents as 6 and 7, and so on, back through the generations. Apart from 1, who can be male or female, all even-numbered descendents are male, and all odd-numbered descendents are female.  It follows that the number of any subject’s father is double the first person's number, and a subject’s mother is double the first person's number plus one. Using this method of numeration, one can derive some basic information about individuals who are listed without additional research.  It becomes a necessary tool because charts or graphs are unreadable after several generations.

In practice, tracing one person's lineage back in time forms a binary tree of parents, grandparents, great-grandparents and so on. However, the number of individuals in such an ancestor tree grows exponentially and will eventually become impossibly high. For example, an individual human alive today would, over 30 generations, and going back to about the High Middle Ages, have 230 or about 1.07 billion ancestors, more than the total world population at that time.  Whereas trace lineage among the vast majority of persons alive today typically involves dating in the hundreds of years—four or five generations—there are a few individuals who can be traced for millennia, and who have millions of descendents.  Genghis Kahn, who fathered hundreds of children, is an extreme example.     

 

In reality, however, an ancestor tree is not a binary tree. Rather, the phenomenon of pedigree-collapse changes the binary tree to what is known as a directed acyclic graph, as seen here.

          

 

 

 

 

 

 

 

This construct displays a person's genealogy neatly and more precisely, without the need for a diagram such as a family tree. It’s useful when it comes to presenting a genealogy in plain text, for example, in e-mails or newsgroup articles. In effect, an ahnentafel is a method for recording numerous individuals in generational order.

Other methods, such as simple lists, are preferable

Notes on Genealogy

(Adapted from Wikipedia)