On a pedigree that is oriented horizontally the vertical lines indicate a reproductive relationship and the horizontal lines indicate the relationship of parent and child. Two short lines crossing a horizontal line typically indicate the end of a committed relationship.
These generational rows are not shown with actual row lines per se. They are just shown through the position of these subjects on the page next to each other. On some genetic pedigrees there may also be roman numerals off to the side that indicate the specific generations. [3] X Research source
Whether a square or circle is filled in gives you key information. A filled in circle or square indicates that the presence of a trait. An empty circle or square indicates the absence of a trait. In some cases there will be circles or squares half filled in. This indicates that the person or animal is a carrier of the trait but does not present with it.
Keys can have explanations of specific symbols, types of lines, and other information that is important for understanding everything on the pedigree. Keys are usually located in a corner of the pedigree.
Most animal husbandry pedigree charts are made for dogs and horses that are pure bred. This means that the animal’s ancestors were all the same breed or variety of animal.
On a pedigree that is oriented horizontally you will look for a horizontal line that is connected to a bracket that is coming off of your subject. This bracket will connect to the subject’s parents.
Explore other ancestral connections. For every generation you trace back there are a variety of relatives in addition to grandparents. For example, look at the subject’s grandparents. Their siblings should be next to them on the pedigree. These people are the grand uncles and grand aunts of your original subject. [5] X Research source
You can also establish that there has been no inbreeding pretty easily by looking at an animal’s pedigree. Look at the familial relationships and ensure that the previous generations of the animal were not bred to close relatives.
Dogs that are pure bred often come with a pedigree chart. These charts typically contain additional information about the dog, including their birth and death dates, their registration numbers, and any titles they have earned. They may also include DNA and health information. [7] X Research source
If there are no roman numerals included on the pedigree you can still easily determine the first generation. Look for the subjects that only have a line indicating a reproductive relationship connected to them. This indicates that the subjects below them are their children and their parents are not represented on the pedigree. The pedigree should also give you information about all of the symbols on the pedigree that are not standard.
A dominant trait is one that is will always be expressed if it is present in someone’s DNA.
Determining who a carrier is can be difficult when a person has several ancestral lines that could be the source of a trait.
For example, if males of every generation have the same genetic trait, then that trait is likely carried on the y chromosome, which females do not have. If a trait impacts both males and females, it is not linked to sex and is carried on a different type of chromosome. This type of trait is called an autosomal trait.
