I hope I am not resurrecting a long dulled discussion, but I have
wondered for some years why we do not attempt to breed a longer lived
dog. As our lifespans lengthen, the gap between the terribly short
lifespan of our companions and our own lives is growing longer. I wish
my 8 yo mixed breed companion could have a longer active, healthy, life
than we can expect.
Canine lifespan is highly variable. True, it is related to size, but
there are some short-lives small dogs and some longer-lived medium sized dogs. (Of course Great Danes are sadly short lived). Size alone is not everything.
Breeding for longevity is, obviously, tougher than breeding for
attributes that manifest early. Still, I can think of a few ways to
begin. The goal would be a mid-sized dog, with a companionable
temperament, with a heathy active lifespan of 13-15 years, followed by
3-5 years of old age. This seems close enough to current canine
lifespans to be achievable without major genetic engineering.
Of course this would not be pure-bred! It would be a new breed that
would take generations to stabilize.
We could begin with long lived healthy male dogs who are still sexually active. They could be bred with young female dogs of a healthy line. A longer-lived mid-sized dog could be crossed with a smaller longer-lived
dog. I suspect dogs with delayed onset of puberty would be likely to
have longer heathy lives, and delayed onset of puberty is obviously much easier to use as a breeding marker than long life.
There are other techniques to consider. We could freeze ova from
potential female candidates (this is done in humans seeking IVF, and is
not a dangerous procedure). Those that had delayed puberty and
physiologic markers of youthfulness in middle-aged could be selected for fertilization from similar males (young females, could, of course, bear
the pups).
Such a breeding program would take time, perhaps 30-60 years, to achieve
the desired goal. The dogs entered in the program would, however, be desireable for their optimized health and vigor. They would also carry
the cachet of being the fore-runners of a new breed of dog.
Comments?
--
John Faughnan M.D.
john@-remove-.faughnan.com
(To form my email address, remove the text -remove- from this string. I
had to do this to foil spam robots.)
http://dragon.labmed.umn.edu/~john/
I posted this 20 years and a few weeks ago. As best I can tell nobody has started work on breeding a health mid-sized dog with a 20 year life expectancy.
Since I wrote this the cost of canine genome sequencing has fallen enormously, and now we can measure telomere lengths, so there are even more tools to use when selecting stored gametes for in vitro fertilization and implantation.
You'd think there'd be a billionaire somewhere who'd give this a shot. We have a lot more billionaires now ...
On Friday, June 27, 1997 at 2:00:00 AM UTC-5, John G. Faughnan wrote:
I hope I am not resurrecting a long dulled discussion, but I have
wondered for some years why we do not attempt to breed a longer lived
dog. As our lifespans lengthen, the gap between the terribly short
lifespan of our companions and our own lives is growing longer. I wish
my 8 yo mixed breed companion could have a longer active, healthy, life than we can expect.
Canine lifespan is highly variable. True, it is related to size, but
there are some short-lives small dogs and some longer-lived medium sized dogs. (Of course Great Danes are sadly short lived). Size alone is not everything.
Breeding for longevity is, obviously, tougher than breeding for
attributes that manifest early. Still, I can think of a few ways to
begin. The goal would be a mid-sized dog, with a companionable
temperament, with a heathy active lifespan of 13-15 years, followed by
3-5 years of old age. This seems close enough to current canine
lifespans to be achievable without major genetic engineering.
Of course this would not be pure-bred! It would be a new breed that
would take generations to stabilize.
We could begin with long lived healthy male dogs who are still sexually active. They could be bred with young female dogs of a healthy line. A longer-lived mid-sized dog could be crossed with a smaller longer-lived dog. I suspect dogs with delayed onset of puberty would be likely to
have longer heathy lives, and delayed onset of puberty is obviously much easier to use as a breeding marker than long life.
There are other techniques to consider. We could freeze ova from
potential female candidates (this is done in humans seeking IVF, and is
not a dangerous procedure). Those that had delayed puberty and
physiologic markers of youthfulness in middle-aged could be selected for fertilization from similar males (young females, could, of course, bear
the pups).
Such a breeding program would take time, perhaps 30-60 years, to achieve the desired goal. The dogs entered in the program would, however, be desireable for their optimized health and vigor. They would also carry
the cachet of being the fore-runners of a new breed of dog.
Comments?
--
John Faughnan M.D.
john@-remove-.faughnan.com
(To form my email address, remove the text -remove- from this string. I
had to do this to foil spam robots.)
http://dragon.labmed.umn.edu/~john/
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