A Breeder’s Guide to Genetics
offers basic information to the “scientifically challenged” and to
beginners. Our modest book is not geared
toward experienced breeders who already possess a sound working knowledge of
genetics. We suggest that such veteran readers
study the previously mentioned mountain of texts written on the subject by
authors with vastly superior knowledge and insight.
The study of genetics, at any
level, should not be a daunting and dreaded chore. It should be fun and, especially at the basic
level, give one the confidence to delve deeper and unravel the fascinating
mysteries of inherited traits. As with
any complex issue, it does not produce “instant experts.”
Merely memorizing the
nomenclature of basic genetic principles does not prepare one to immediately
defend strong opinions on a subject as multifaceted as this. Studying them, however, should serve novice
breeders and those who decide to approach their breeding program with careful
planning to lend it structure and purpose.
From our own background of interests and experiences, Denise and I will
explain concepts primarily using data about various dog breeds and camelids. We hope
the reader will understand that basic genetic principles apply to all species,
including Man.
We both believe that no story is
too foolish to serve as a simplified example to promote the understanding of
educational ideas. Therefore, I have not
shied away from employing whimsical – and sometimes downright silly – descriptions to
illustrate necessary points. The more
serious-minded scholars among you might find my methods too “unscientific” for
your sensibilities. It’s okay. We aren’t easily offended.
Most breeders, if they are
anything like me, do not retain technical information the first time it is presented. Consequently, you will see many little
reminders and memory boosters along the way.
The few geniuses with perfect memory will just have to suffer through
the repetitions.
If, after a quick glance, you
decide the chapters on the cell, DNA, and genomic imprinting are too difficult
and confusing, just skim over them. Then
return to them later to gain a deeper understanding of genetic
inheritance. Perhaps that’s putting the
cart before the horse. So what? That sequence worked well for me, although it
is a longer route to take. I am no
wizard in the field of science.
My spirits were boosted
considerably when I learned that Gregor Mendel failed
his admittance exams to study physics and natural science at the University
of Vienna – twice! The first time he failed because he had not
mastered the material, the second time because he argued with the
examiner. You see – there is always
hope!
Years ago, I didn’t realize that
the knowledge of pure science (genetics) is a prerequisite for the true
comprehension of breeding programs. My desire to understand the “system” behind
the various breeding options available probably made all the difference. I finally overcame my fear of pure science
and succeeded where previously I had only experienced confusion and defeat.
When I learned of the enormous
contributions German and German-American scientists made and continue to make
in the field of genetics, I couldn’t help but wonder what contributed to my own
genetic make-up. My family did not show
much interest in the subject. I do
remember my father’s reply when my petite sister expressed concern about the
size of her truly tiny daughter. “What
did you expect?” he asked, looking from my sister to her equally short
husband. “Mice make mice.”
True enough in most cases, but
there are times when, metaphorically speaking, they produce elephants.
I occasionally use human examples
to discuss or clarify concepts about animals.
We like to think of ourselves as unique and so different from all
mammals lacking our speech patterns and opposable thumbs. We are not!
The basic components that make up the DNA of dogs, llamas, and all other
critters make up the DNA of their two-legged caretakers as well. What is the difference? The sequence in which the nucleotides’ bases appear
in the DNA chain differs in the various species. Is that it?
That’s it! What’s more,
specific human DNA sections are identical to those of “other” animals.
The April 2000 Newsweek
issue featured a short article about gene sequencing in the fruit fly. What is the significance of having the fruit
fly’s genome “read” and understood? In Thomas Hayden’s words:
“... because some two-thirds of genes associated with illness in people
are also found in Drosophila. The
new data should help researchers to further explore the causes of human genetic
disease.”
Canine DNA research has advanced
more quickly due to the interest in genetic defects “shared” by Man and his
most faithful companions.
We can now appreciate that
gaining genetic knowledge about one species can help us to become more
successful breeders of other species.
When I researched data for this
book, I was referred to a sheep breeder to learn more details about Spiderleg syndrome.
After we had talked for a while, the breeder’s wife commented, “You
breed alpacas and dogs – why do you want to know anything about sheep?” Some dog breeders