Animal Behavior Consultations, LLC, Brooklyn Veterinary Hospital, 150 Hartford Rd., Rt. 6, Brooklyn, CT 06234, USA.
Behav Genet. 2011 Nov;41(6):858-75. doi: 10.1007/s10519-011-9452-7. Epub 2011 May 15.
Although there are minimal genetic differences between the coyote (Canis latrans), the gray wolf (Canis lupus), and the domestic dog (Canis familiaris), these three species are extremely different in numerous aspects of their physiology, morphology, and behavior. In particular, the threat display of coyotes differs markedly from dogs and wolves. Coyotes display a wide open mouth gape-threat with attendant arched back defensive posture, and hiss vocalization. In our experience, this threat display is absent from the repertoire of the domestic dog and the gray wolf. We hypothesized that the foundation of these differences in species-typical threat displays is genetic. The threat displays of coyote-beagle crosses (F1's, F2's, F3's, F1F2's and beagle backcrosses), included the following phenotypes: that of each parental species, that of the domestic dog during pre-pubertal development switching spontaneously to the coyote gape-threat following sexual maturation; and a comparable phenotype requiring exposure to post-pubertal social stress-priming to bring the encoded genetic potential for the gape-threat to expression. The changeover from the dog snarl-threat to the coyote gape-threat was accompanied by a precipitous rise in endogenous cortisol levels over baseline. We hypothesized that where alternative genetic systems are physically available, their selective expression in development may depend on environmental events, such as social stress, to affect internal mechanisms that ultimately control the phenotype. Exogenously elevated cortisol levels, in the absence of the subjective experience of social stress, were associated with the onset of the expression of the coyote threat pattern in an F1 hybrid possessing a full haploid complement of coyote genes and his backcross offspring resulting from a breeding to his F2 daughter. With oral doses of hydrocortisone, the cortisol levels were substantially elevated over basal levels. With endogenous cortisol priming, an increase up to five-fold over those levels obtained with social stress was associated with the expression of the coyote phenotype.
虽然郊狼（Canis latrans）、灰狼（Canis lupus）和家犬（Canis familiaris）之间存在最小的遗传差异，但这三个物种在生理、形态和行为的许多方面都有很大的不同。特别是，郊狼的威胁表现与狗和狼有明显的不同。郊狼表现出张口威胁，伴随着弓背防御姿势和嘶嘶的发声。根据我们的经验，这种威胁表现在家犬和灰狼的行为中并不存在。我们假设这些物种典型威胁表现的差异的基础是遗传的。郊狼-比格犬杂交（F1、F2、F3、F1F2 和比格犬回交）的威胁表现包括以下表型：每个亲本表型、性成熟后犬在青春期前发育期间自发切换为郊狼张口威胁的表型、以及一种类似的表型，需要暴露于青春期后社会应激-引发，以表达编码的张口威胁遗传潜力。从犬的咆哮威胁到郊狼张口威胁的转变伴随着内源性皮质醇水平相对于基线的急剧上升。我们假设，在存在替代遗传系统的情况下，它们在发育中的选择性表达可能取决于环境事件，如社会应激，以影响最终控制表型的内部机制。在外源性皮质醇水平升高的情况下，在没有主观社会应激体验的情况下，与在具有完整郊狼基因单倍体的 F1 杂种中表达郊狼威胁模式以及从他的 F2 女儿繁殖而来的回交后代有关。使用口服氢化可的松，皮质醇水平相对于基础水平显著升高。在皮质醇引发的情况下，与社会应激相关的水平增加五倍与郊狼表型的表达相关。
