Inheritance – it’s not just money from your mom and dad
Each month, we explain a few questions from the Golden Retriever Lifetime Study questionnaire.
The Golden Retriever Lifetime Study provides researchers with a unique opportunity to study the interaction of the environment with genetics in a group that shares many genetic similarities but also have subtle differences. Comparing health data between siblings, dams, sires and unrelated dogs will give us new insights into how specific genes (a biological inheritance) might correlate with health outcomes.
Questions two through 45 of the three-year questionnaire and questions 22 through 50 of the veterinary questionnaires ask detailed questions about diseases of the dam, sire and siblings of study participants. The high number of questions devoted to our participants’ dog’s “family” underscores the importance of analyzing genetics in the Golden Retriever Lifetime Study.
Genetics is more complicated than simply decoding an individual’s genetic make-up, and the outward expression of inherited DNA depends on many variables. In order to make sense of the genetic data we’re collecting, we need to know a little about how specific traits are inherited.
People, and animals, can look very much like their parents. People also can be very different in appearance from their parents, but look like other family members (like a grandmother or an uncle). In some families, one sibling looks like one parent, but another looks like the other, and a third is a combination of both. In theory, the same genetic material is available to all offspring; if so, how can they be so different?
Chromosomes are molecules that contain genetic material. We inherit chromosomes in pairs, made up of one chromosome from each parent. This is true for almost all complex organisms, from tomatoes (12 pairs) to dogs (39 pairs).
When eggs and sperm are created, they get only one chromosome per cell – remember, each parent is contributing one chromosome to their offspring. It is random which one of a parent’s two chromosomes end up in the egg or sperm. To complicate matters, chromosomes often will swap little bits of DNA with each other, a process called recombination. This process leads to subtle differences between chromosomes that get packaged into each sperm and egg, and this results in the diversity we can see between siblings.
In humans, an incredible amount of work has been done to understand the inheritance patterns of certain traits. The Golden Retriever Lifetime Study should help to provide veterinary genetics researchers with new insights into inheritance patterns in dogs.