BETWEEN THE LINES
BO
BENGTSON
line to improve type.
s long as dog shows, stud books and pedigree
Who knows, those “out-
records have existed, successful breeders of
crosses” may also have
purebred dogs have mostly followed the same
introduced an extra, very
formula: linebreed or inbreed to the best individuals,
necessary dose of strength
concentrate the bloodlines and outcross only when nec-
and vitality.
essary. (And even those “outcrosses” are generally, if you
How long can you keep in- and
look further back in the pedigrees, based on the same
linebreeding within a closed gene
foundation dogs many times over). When you look at old
pool without producing ill effects? A
pedigrees, it’s amazing how close those early breeders
dozen generations? Twenty or thirty?
dared to go: half-brother to half- sister, even full siblings
I am not a geneticist, but it’s clear even to
bred together; sire to daughter, grandsire to granddaugh-
me that when you’re breeding closely relat-
ter with an uncle thrown in on the “unrelated” side,
ed dogs in an attempt
etc. etc. It says a lot for the basic
to “set” some desir-
soundness of the foundation stock of
able characteristic,
most breeds that there were seldom
Of course, breeders
you may inadvertent-
visible ill effects of all this close
in the past believed
ly also double up on
breeding. These dogs’ backgrounds
a few things that you
usually varied considerably; in many
strongly in the
don’t want and that
breeds their pedigrees were some-
“survival of the
may not be immedi-
times unknown well into the 20th
fi ttest” theory:
ately visible to the
century, and close inbreeding was
naked eye.
necessary to “set” the breed type.
they were a lot less
Modern science tells
emotional than we
us that most genetic
Changing Mores
are today about the
disorders in dogs are
Of course breeders in the past also
caused by a single gene
believed strongly in the “survival of
odd puppy that was
that was somehow damaged
the fittest” theory: they were a lot
not doing well.
but remains hidden and has
less emotional than we are today
no ill effects as long as the
about the odd puppy that was not
animal also has a copy of the nor-
doing well. We don’t discard a single
mal gene. Things get serious when this damaged gene
puppy if we can help it—and with modern veterinary
becomes common enough in a breed that two apparently
care we usually can help it; in those days they would
healthy animals, both with a copy of the damaged gene,
just, to use a blunt but very descriptive term, “bucket”
are bred together and their offspring has to suffer the
such a puppy. If it wasn’t strong and thriving it wasn’t
consequences.
worth fussing over, and it did not grow up to propagate
Apparently genetic disorders in dogs caused by these
the species.
recessive mutations usually appear suddenly: “I’ve never
In the early days there was also in many breeds a
seen this before,” you say, genuinely surprised when
silently accepted, but almost never openly discussed,
encountering a “new” problem in a litter or an adult dog.
habit of