Dog Breeding Genetics : Expression of Genetic Traits


What will those puppies look like ? Tell me what I need to know ! Ok… Sure… You see we might indeed use the term “genetic lottery”, however, you don’t want to rely on a crystal ball here ! You can be very accurate,
especially if you have a good understanding of the following concept : Expression of Genetic Traits. That’s what today’s episode is all about. So let’s dig into this. Hello everyone ! I’m Dr E and on this channel,
I share with you what I know on management of kennels and catteries. If you are new here, and you want to improve
your knowledge and your skills in this field, consider subscribing. And right now guys, we are on a journey, a genetic journey to be exact because this video is part of my “Genetics Masterclass for dog breeders”. So during those short presentations, I will
teach you the basics you need to know before starting working on your breeding program. So today we are talking about the expression
of genetic traits. And I’m going to cover 4 things that you absolutely
need to know here. Genetics comes with a lot of definitions,
its own lingo that you need to master, to fully grasp the meaning of this science. And to my point, here is an example we talked
about in our previous video: PHENOTYPE and GENOTYPE. A PHENOTYPE is an individual’s observable TRAITS, such as height, eye color, blood type. The genetic contribution to the PHENOTYPE
is called the GENOTYPE. “Traits”, simply put, are what you can observe
on an individual. Like the color of the coat, the height, the
morphology. Characteristics that you can indeed appreciate
and evaluate. That’s what you focus on when you are in charge
of a dog breeding program. You want to obtain them, you want to improve
them. Because again, this is how you will reach
your WHY. Those traits are, to some extent, influenced
by the genetic material our dogs have inside their cells. All traits are not made equal though. Time to deep-dive into this concept ! Your
breeding selection program is all about your WHY. I already told you that ! Well, time to put
this into practice ! Here is what you need to do in real life. Grab a notepad ! Yes, you heard me right ! Grab
a notepad and a pen because I want you to do a preliminary exercise. So now, write down on the notepad I asked
you to grab those traits you want to select your dogs for in your breeding program. You can pause the video while you are doing
that, I’m not going anywhere, I can promise you that ! Ok now when you are done writing,
I want you to take the page out of the notepad and put it next to a blank one. Because we are now going to split those traits
into 2 categories. The ones that are said to be qualitative. Versus the ones that are said to be quantitative. A QUALITATIVE TRAIT defines a quality. That means that the different phenotypes you
will observe will fall into different categories. Let me give you a few examples here. Color of the coat. Color of the eyes. Type of coat, if it is smooth, rough, curly. On the other hand, a QUANTITATIVE TRAIT is
something that can be measured. In fact anything that can be measured will
fall into this category. Again, few examples here. Height. Weight. Age. Those 2 different types of genetic traits
have what we call different types of genetic determinism. They are influenced in a different way by
genetics. For the purpose of this video, we will only
focus here on qualitative traits. Hey don’t you worry, I’ll definitely shoot
a video on the quantitative ones as well. So stay tuned to this channel if you don’t
want to miss it. So now let’s see how those qualitative traits
are transmitted. Qualitative traits are often called monogenic. Because typically only one gene is involved in it. Quick question for you guys : what is a gene ? Do you have a clear definition of what this is ? So let’s take a given chromosome inside
the dog’s genome. To keep it super simple, a gene is a DNA sequence
that is located on a very precise location inside the genome. And we call this locus if you want to use
fancy terms ! A given gene is therefore located at a given position on a given chromosome. It is not moving around. It stays on this chromosome it is meant to
be on in the dog. In dogs, in all mammals by the way, chromosomes
always come by pairs. Which means, that for one given gene, in a
dog, you will always have two copies of this gene. Those 2 copies they can be the same. Or they can be different. Because there are indeed different versions
of a gene, born from mutations happening in the species. Those different versions, we call them ALLELES. That is a very important term for you guys
to remember because this one, I can guarantee you, comes back all the time in discussions
around genetics. An allele represents a version of a gene. And for a given gene you can have multiple
alleles. Ok so we just covered some very important
concepts. They will come in handy for the next step. Understanding the underlying mechanisms behind
the expression of qualitative genetic traits. So let’s take a simplified example that I
always use in my lectures. The color of the coat in Labrador Retrievers. If you want to take a look at the real thing
in Labradors, I really encourage you to watch this webinar we did recently on Genetics in
Labradors. So our gene, in this example, would be coat
color. And in this simplified example, this gene
exists in 2 versions, again 2 alleles. B+ and b. B+ means black. b means chocolate. So you see here we have one gene, two alleles. That means that in a dog, you have 3 possibilities. For this gene, a dog can be B+B+, B+b, or
bb. One gene, 2 alleles, 3 possibilities. Those 3 combinations you have here, that’s
what we will call the genotype. And here, when you know the genotype, in qualitative
genetics, you can now define the phenotype of the individual. So you see, this dog, B+B+, its coat will
be black. This one, bb, will be chocolate. And what about this one (B+b) ? A mix of both
colours ? That is a very common answer I get when I give this lecture ! This one in fact is black. It is black because the allele B+ is dominant. And here we are with a new concept you guys
need to be aware of : the Law of Dominance. You see, there is a hierarchy between alleles. Some are dominant, some are recessive. When the dominant is present, well, basically,
the recessive cannot say a word. The recessive allele cannot be expressed when
the dominant is present. It does not get more simple than this. In my example here, B+ is dominant. And b is recessive. Anytime B+ is present, the dog is black. For a dog to be chocolate, it must be bb. And there is no other way around this. And believe it or not, I have more definitions
to throw in here ! You see here, B+B+, bb, for the gene we are interested in, color of
the coat, the 2 alleles, those 2 versions of the gene the dog carries, they are the
same here. When this happens, we will say that the dog
is HOMOZYGOUS for the gene. In the case of B+b, for the gene of interest,
the dog carries 2 different alleles. It is therefore said to be HETEROZYGOUS for
the gene. We could also say it is a black dog carrying
chocolate. Heterozygous, homozygous… Again those are big words here. And you might wonder why you need to know
this. The fact is, those are regularly used in genetic
lectures, genetic textbooks. You want to feel more comfortable in this
field ? You need to know what they mean ! I am not kidding here ! So in this video, we
reviewed very important concepts. The final goal for you however is to grab
those concepts and use them to reach your WHY you spent so much time defining. Next time we will see how we can harvest the
power of genetics. Thank you guys for hanging out with me today ! If you enjoyed the video, give it a thumbs up ! And share it on your favorite social
media networks ! Sharing is caring, that’s what we content creators say. If you want to support this work, well that
is the simplest way to do it ! And if you are not following us already, please hit this subscribe button. So you won’t miss any of our future videos ! Have a great day guys ! We will see each other very soon, on the next video ! You can be sure of that !

5 Comments

  1. Gernoasje March 14, 2018 at 1:30 am

    Just a little remark. Not all genes have the same trait. For ex the M gene in coat colour is an exception.

  2. Northern Force Bullies Authentic Shortybulls November 28, 2018 at 4:27 am

    Can you do a video on a genetic sequence , how you read them and how you would know which color the canine carries . Thanks very interested in coat color

  3. Russel Richard Doctolero December 27, 2018 at 10:17 am

    Please keep posting this kind of video it help alot of peaple

  4. Mark Ballard November 13, 2019 at 3:09 pm

    I'm glad I came across this video. I hope you are still available. I see it was uploaded over a year ago. I have contacted many prominent dog breeders with my question with no response. Ok, often breeders speak of throwbacks. Perhaps they have had some great dog in the past with a certain build, color, and/or temperament. After several generations of linebreeding based on this individual, there comes a pup who looks just like him, maybe even have the same temperament. Can we assume that because of these similarities that this pup will be like this dog in every way, even in ways they aren't apparent just by looking at him? In other words are traits connected? Like in the case of the domestication syndrome.

  5. King Salomon November 14, 2019 at 9:52 pm

    How do you bred for high prey drive or Aggression?

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