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How to Read a Pedigree
by Kim Richardson 

One of the most basic of breeder tools is the pedigree. A pedigree is a written document that records the heritage of any given animal, a family tree.  Breeders use these to see the potential genetic makeup of an animal and to help select their future breedings.

 How do you read them?  What does it all mean?  No matter what type of animal pedigrees all have the same basic format.  I will now explain some of the basic pedigree elements.  This of course is specific to rats but the basic structure would be the same whether cat, dog or horse.

Naming Conventions:

 Naming conventions are relatively the same throughout the species.  Most breeders have a “Rattery Name” for example mine is Landmark Rattery. My prefix letters are LMR.  Every rat that I breed has an LMR before the name.  When looking at a pedigree if you see a rat with a name starting with LMR then you know it was bred by Landmark Rattery.  A suffix indicates ownership so a rat named something of LMR would indicate that it was owned by Landmark Rattery.  LMR Pudding SRR would indicate a rat bred by Landmark Rattery but owned by Spoiled Ratten Rattery.  A listing of known rattery prefixes can be found on The Ratster www.ratster.com. The breeder is the person who owned the dam at the time of conception.  Understanding and using the naming convention helps when looking at pedigrees because with a glance you can tell which ratteries the ancestors of your rat came from.  This would be important information when deciding whether to breed your rat or not and if so to which rat.

 It is important that you never change a rats name on documents such as pedigrees.  Over the years a rat known as XXX Sunny on one pedigree and then later as XXX Sunny YYY will appear to be two separate rats.  I’ve even seen a rat that was known as XXX Sunny YYY and then was sold to another owner and they changed his name to XXX Sunny ZZZ to someone researching  those pedigrees this appears like two different rats, when it is indeed the same rat.

 Terminology:

The father of a rat is called the sire and the mother is a dam.  A generation is a complete listing of heritage.  So for example a one-generation pedigree would be a listing of the rat’s parents; two generation is the rat’s parents and grandparents; and three generations is the rat’s parents, grandparents and great-grandparents.  Pedigrees can go back as many generations as you know the information.

 Recording Lineage:

 Just looking at a pedigree it doesn’t appear to be in any specific order… but it is.  There are several different ways to list lineage.  When stating in sentence form the words by indicate the sire and out of indicate the dam. By (sire) out of (dam)  for example… a litter is by LMR Bilbo Baggins and out of LMR Oprah Winfrey.  When listing parentage the sire is first and the dam second in any format.  If you wanted to list a rat and it’s parents the format would be Rat’s Name (Sire x Dam)  for example:  LMR Forest Gump (LMR Bilbo Baggins x LMR Oprah Winfrey). 

 There are many different formats for a pedigree.  Some have brackets, some have boxes, or you could have lines or even just spaces.  It all depends on what you prefer and if you are using a pedigree program.  No matter the format they should always have the sire on top and the dam on the bottom.  This is one of the biggest mistakes on pedigrees to date.  Pedigrees with the doe on top and the buck on bottom, make it very confusing to read and if the names aren’t obviously sex specific rats can get mis-sexed.  For example a rat named XXX Sunny could be a buck or a doe.  If it’s on the top, it will be recorded as a sire.  

Pedigrees read  from left to right.  Some pedigrees such as the example above list the rat, of which the pedigree is for,  at the top and then underneath begins with the sire and dam.  Subsequent generations are then added to the right of the previous one, following the flow of Sires on top and dams on bottom.   The pedigree in the example below lists the rat then the sire and dam.  Both are correct, depending on how many generations you are planning to list, the format, and how much room you have on the paper.  The animals listed  farthest to the right are the more distant relatives.

Rat

Sire

Sire’s Sire

Sire’s Dam

Dam

Dam’s Sire

Dam’s Dam

 The rat is listed then its sire, sire’s sire, Sire’s dam, Dam, Dam’s Sire, Dam’s Dam.

Important information to include on pedigrees is a brief description of the rat such as color, markings, coat/ear type, and any additional information you may have which could help someone reading the pedigree; such as date of birth, date of death, and registration numbers.   That will greatly help anyone in the future that happens to be linechasing from your lines.  Linechasing is a hobby of researching pedigrees in animals.   It has been rather difficult to linechase rats due to the fact that many breeders haven’t been keeping adequate records.  With the introduction of the NARR it's becoming a reality.  In the years to come people will be able to research their rats heritage back far more generations than they have ever dreamed.  This can only be possible with  breeders keeping better records and of course the work of the NARR.

Pedigree Programs:

There are many programs on the market for recording pedigrees. One of the most popular among rat breeders is Breeders Assistant.  There is even a version designed around rat keeping.  This program will make sure the formatting of your pedigrees is correct and you have many options of selecting what information you want printed on pedigrees etc.


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