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[news] Injured dog's selflessness draws tears
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what an amazing story! thanks for shari [more ...]

[news] Gene Causes Canine Compulsive Disorder in Suspectable Dog Breeds
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this is a test comment for Jessica

[links_page] Molosser Dogs
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I just had to put a comment on this one. [more ...]

[news] Unwanted Canine Guests: Internal Parasites
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Genetics-An Introduction for Dog Breeders


Moderators: maximus, jessica, All about Eva, Igmuska

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jessica

Mon Nov 22 2010, 09:30AM

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"Excerpt: Nature or nurture which determines behavior? The answer is neither one alone. No instinct is completely determined by heredity; no social, cultural, or learned behavior is purely environmental. Behavior always develops through the interaction of both hereditary and environmental factors.
Behavioral genetics is the study of organisms by means of both genetic and behavioral analysis; it is an interface between the two sciences. Like other hereditary traits, behavior is a phenotype that can be observed and measured. Unlike physical traits, behavioral phenotype influences the entire organism, making it the most dynamic of all hereditary traits as well as the most responsive to environmental changes.

HOW DO GENES AFFECT BEHAVIOR?
The precise way in which genes affect behavior is not yet clear, but knowledge is growing by leaps and bounds. What is known so far is tantalizing.

EFFECT ON STRUCTURAL TRAITS
The genes provide instructions for producing proteins, and some of those proteins play a role in behavior. Their first effect is to create the brain and nervous systems.

The structure of the brain and nervous system of a fruit fly is very different than that of a frog. The closer the relationship between animals, the fewer their structural differences. The brains and nervous systems of mammals such as dogs and wolves or humans and chimpanzees have many structural similarities.

The structural traits immediately set limits on the type of behavior that each creature can possibly achieve. The behavior of animals that are low on the evolutionary scale is almost completely instinctive that is, programmed by the genes. Surprisingly, even fruit flies can learn to avoid shocks and to recognize different odors. This, too, is hereditary, and some strains learn more quickly and have better memories than others. As the brain and nervous system become more sophisticated, behavioral patterns become more complex, and the potential for learned behavior increases.

THE GENETIC CALENDAR
Behavior is also attuned to a genetic time clock. Genes turn on the behavior appropriate for puberty, mating, and raising young. There are daily genes that influence the patterns of the feeding and the wake-sleep cycles. Annual cycles, such as mating and migration, respond to seasonal changes such as the length of daylight.

HORMONES AND BEHAVIOR
Genes produce many hormones that play important roles in behavior. Hormones are produced not only by the endocrine system but also by cells throughout the body. Although the endocrine system and the nervous system are anatomically distinct, the physiology of the systems are intricately interwoven. The nervous system is mediated by the endocrine system, and the endocrine system is controlled by the nervous system. The domesticated silver foxes described in Chapter 1 illustrate the complexity of these relationships.

Neurohormones are any biochemicals produced by or acting on nerve tissue are produced in the brain as well as throughout the nervous system. They interact with neurotransmitters substances that transmit nerve impulses across synapses and influence behavior by initiating or modifying the transmission of nerve impulses. The neurotransmitters act in response to the environment. Fear, for example, floods the body with fight-or-flight neurohormones. Although the interplay of neurotransmitters is inherently an automatic, involuntary response, it can be modified in several ways. If an individual is repeatedly exposed to a frightening stimulus that never actually causes harm, the response becomes less intense or disappears. Humans can exert remarkable conscious control over their neurotransmitters through biofeedback techniques. Neurotransmitters are also modified by ingested substances. This can be beneficial in the case of mental disorders, and it can be harmful in the case of cocaine.

Arons studied the genetic variability of predatory behavior toward sheep in three breeds of dogs representing different functional types using neurochemical analysis. Siberian Huskies exhibit the complete predatory behavior pattern and are consistent killers of livestock. Border Collies represented the herding dogs that exhibit an inhibited predatory response. Shar Planinetz, developed to protect livestock, have low level of interest in sheep and exhibit little, if any, predatory behavior, and they had the lowest level of catecholamines (a group of biochemicals that function as neurohormones or neurotransmitters).

Stress alters the levels of neurohormones such as nor epinephrine, dopamine, and serotonin. An example of the heredity of stress-related neurohormone levels has been identified in a strain of genetically nervous Pointers. The dogs behave normally when not under stress, but freeze and exhibit other abnormal behavior in unfamiliar (stressful) situations. Comparative biochemical assays have found that these dogs have increased levels of nor epinephrine and decreased serotonin and dopamine.
Stress plays havoc with the endocrine system and even with the bodies homeostasis (the ability to maintain physiological processes within normal limits despite varying external conditions). Furthermore, it sometimes impairs the immune system, leaving the individual vulnerable to infections that might have been easily overcome by normal body defenses. The incidence of cancer is higher during the five years following extreme stress, such as the loss of a loved one. The effect of long-term stress is less clear, but some permanent physiological damage is suspected. Many people who develop clinical depression under extreme stress must remain on antidepressants for years, sometimes for the rest of their lives. Symptoms of depression have been observed in chimpanzees, and the incidence appears to parallel that in humans, which is another indication of similar biochemistry.

Evidence that some mental disorders are related to disturbances of neurohormone levels is growing. Many drugs that are used to treat these disorders appear to act by restoring the normal balance of neurohormones. What is not clear is how much is genetically predetermined and how much is environmentally induced. Disorders such as schizophrenia and attention deficit disorder show such pronounced familial patterns that hereditary factors are suspected.
By Jackie Isabell"

Poseidon

Sat Nov 27 2010, 04:49PM

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"Arons studied the genetic variability of predatory behavior toward sheep in three breeds of dogs representing different functional types using neurochemical analysis. Siberian Huskies exhibit the complete predatory behavior pattern and are consistent killers of livestock. Border Collies represented the herding dogs that exhibit an inhibited predatory response. Shar Planinetz, developed to protect livestock, have low level of interest in sheep and exhibit little, if any, predatory behavior, and they had the lowest level of catecholamines (a group of biochemicals that function as neurohormones or neurotransmitters)."

I found this part interesting.

Igmuska

Sun Nov 28 2010, 06:12PM

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The most interesting part is the inhibition is a timed triggered gene. As the other two are learning the predatory responses, the Sar is inhibited, and expresses this stage later in growth, therefore not developing the proper "function."
Neat stuff. I have seen a Sar kill and eat vermin, and kill wolves, yet they have this inhibition towards livestock and greater prey animals. Interesting stuff...

FARRUGIA

Wed Dec 01 2010, 05:02PM

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Intersting stuff in this thread,being someone who has bipolar assumed to be inherited from my father as he also has it and having 3 other siblings I have the disorder and one of my sisters does too,yet my other brother and other sister do not ,so would it be prudent to hypothesise that there exists a 50 50 possibility of passing on character related straits from a genetic stand point and that tho we may test a dog and find some adverse charcater traits which we assume to be genetically inherited yet has some above average physical manifestations which seem to be accepted as also being genetically inherited and given that ,certainly from a human stand point , not all genetic traits are past on at least not to all ospring,is culling or non breeding still desirable.

Furthermore tho I have inherited bipolar and can say that tho that is a disorder I have in common with my father and one of my sisters ,I can say that we are each different individuals and not totally defined by the disorder.To quote a consultant psychiatrist " I am not bipolar,I am Andrew with a bipolar disorder.

To add more interest to the topic there are other disorders that exist that once diagnosed the knowledge of diagnosis far from making it a negative can be a positive in that once the knowledge of diagnosis is achieved,in many instances with appropriate interventions from an educational point can be implemented and allow the person or animal with the disorder to be normalised and put back on par with orther non disordered beings ,as with something like dyslexia .

If we take into account as mentioned in one of the above posts where there may have been exposure to adverse enviromental influences which often . in humans,can result in "post traumatic stress disorder,PTSD" something I have or had but again knowledge and diagnosis have opened up the way to treatments to overcoming and conquering.

In comclusion whilst testing may reveal negative characteristics inherited or enviromental would it not be more productive to understand more about the latter and different approaches to bring up such dogs tailored to normalise the dog or individual so that they may overcome there individual deficiencies and be trained ,and cared for in away that with appropriate aproaches allows " just as good" sinario to occurr.Obviously once identified a dog with undisirable characteristics will need to be passed on or sold to a place where they na have the benifit of someones knowledge of both the deficiency and the knowledge of the best and appropiate upbringing,not an easy task but one a responsible breeder must strive to achieve as it is thier ultmate responsibility to do the best for what they have produced .Sadly there are too many breeders that do not have the knowledge of what to or how to test for these things and are further lacking in thier commitment ,may be because it's too much effort ,.So my opinion is that tho many will breed dogs that lack all the deirable things wewould like to see there should be nothing more satisfying for a breeder to place such dogs so as to enable them to have just as good an existance as the "closer perfect specimen"

Andy UK

Igmuska

Tue Dec 07 2010, 08:28AM

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Good post. I agree with you. One breed I am involved in has serious neurological issues. I "push" my dog not only because I enjoy (we both rather) the sports and activities I train my dog in, but because stresses can and do help expose and manifest neurological instabilities.
Nurture triggers nature. well placed nurture can also hide nature as well. Regarding your personal example, would you say that your siblings potentially carry the condition while not expressing symptoms? IMO, this is what makes breeding difficult. There is a wonderful book written by a DVM here at the college. It discusses different inheritable diseases, their prevalence in a breed and what we know about the inheritance of said diseases. Worth a read for any breeder. It was written in 1998, and Dr. Padgett has expressed interest in revising the edition.
"Control of Canine Genetic Diseases" by George A Padgett, DVM.

FARRUGIA

Thu Dec 30 2010, 01:56PM

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Having spoke to my consultant,it is indeed possible that the condition can still be past on from my siblings not showing any symptons but has a lesser chance of doing so.Quite an ordeal to produce perfection or close to it but still worth the effort to give it our best efforts

jessica

Fri Dec 31 2010, 01:27PM

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Joined: Fri Jun 20 2008, 02:11PM
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It is.....This is Why a breeder has to follow as many dogs that they produce as possible. Not to mention study the family tree and find out what health issues (if possible-most do not want to share) is in the past.


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