RESUMEN
Thermal performance curves (TPCs) are continuous reaction norms that describe the relationship between organismal performance and temperature and are useful for understanding trade-offs involved in thermal adaptation. Although thermal trade-offs such as those between generalists and specialists or between hot- and cold-adapted phenotypes are known to be genetically variable and evolve during thermal adaptation, little is known of the genetic basis to TPCs - specifically, the loci involved and the directionality of their effects across different temperatures. To address this, we took a multivariate approach, mapping quantitative trait loci (QTL) for locomotor activity TPCs in the fly, Drosophila serrata, using a panel of 76 recombinant inbred lines. The distribution of additive genetic (co)variance in the mapping population was remarkably similar to the distribution of mutational (co)variance for these traits. We detected 11 TPC QTL in females and 4 in males. Multivariate QTL effects were closely aligned with the major axes genetic (co)variation between temperatures; most QTL effects corresponded to variation for either overall increases or decreases in activity with a smaller number indicating possible trade-offs between activity at high and low temperatures. QTL representing changes in curve shape such as the 'generalist-specialist' trade-off, thought key to thermal adaptation, were poorly represented in the data. We discuss these results in the light of genetic constraints on thermal adaptation.
Asunto(s)
Adaptación Fisiológica/genética , Drosophila/genética , Variación Genética , Sitios de Carácter Cuantitativo , Animales , Drosophila/fisiología , Etiquetas de Secuencia Expresada , Femenino , Masculino , Actividad Motora , Análisis Multivariante , Mutación , TemperaturaRESUMEN
Thermal performance curves (TPCs) provide a powerful framework for studying the evolution of continuous reaction norms and for testing hypotheses of thermal adaptation. Although featured heavily in comparative studies, the framework has been comparatively underutilized for quantitative genetic tests of thermal adaptation. We assayed the distribution of genetic (co)variance for TPC (locomotor activity) within and among three natural populations of Drosophila serrata and performed replicated tests of two hypotheses of thermal adaptation--that 'hotter is better' and that a generalist-specialist trade-off underpins the evolution of thermal sensitivity. We detected significant genetic variance within, and divergence among, populations. The 'hotter is better' hypothesis was not supported as the genetic correlations between optimal temperature (T(opt)) and maximum performance (z(max)) were consistently negative. A pattern of variation consistent with a generalist-specialist trade-off was detected within populations and divergence among populations indicated that performance curves were narrower and had higher optimal temperatures in the warmer, but less variable tropical population.
Asunto(s)
Adaptación Biológica , Drosophila/genética , Locomoción , Carácter Cuantitativo Heredable , Temperatura , Animales , Australia , Femenino , Variación Genética , MasculinoRESUMEN
OBJECTIVE: To determine the incidence and describe ocular abnormalities in a cross-section of the population of Rocky Mountain Horses. Design: Prospective study. Animals: Five-hundred and fourteen Rocky Mountain Horses. Procedure: Ophthalmic examinations were performed using a slit-lamp biomicroscope and an indirect ophthalmoscope. Intraocular pressures were measured by applanation tonometry. Eyes from six horses were obtained for histologic examination. RESULTS: Cysts of the posterior iris, ciliary body, and peripheral retina were detected most frequently (249 horses), and were always located temporally. Curvilinear streaks of retinal pigmented epithelium extending from the peripheral temporal retina marked the boundary of previous retinal detachment in 189 horses. Retinal dysplasia was detected in 125 horses. Multiple ocular anomalies were evident in 71 horses and were always bilateral and symmetrical. Affected eyes had a large, clear cornea that protruded excessively and had an apparent short radius of curvature, a deep anterior chamber, miotic and dyscoric pupil, and iris hypoplasia. Pupillary light responses were decreased or absent and pupils failed to dilate after repeated instillation of mydriatic drugs in horses with multiple ocular anomalies. Less frequently encountered abnormalities included peripheral iridocorneal adhesions and goniosynechiae. Congenital cataract was always present in eyes with multiple abnormalities. Intraocular pressures did not differ among horses with normal eyes and horses with multiple ocular abnormalities. Histologic examination of eyes corroborated the clinical appearance.
RESUMEN
Effects of topical administration of a single dose of timolol maleate on intraocular pressure (IOP) and pupil diameter were evaluated in normotensive eyes of 11 clinically normal dogs over 12 hours (7:00 AM to 7:00 PM). Mean (+/- SEM) normal IOP was 15.5 (+/- 1.1) mm of Hg and diurnal fluctuation was observed, with the highest IOP seen in the morning. Mean normal pupil diameter was 8.5 (+/- 0.3) mm. Topical treatment with 0.5% timolol resulted in reduction of IOP in the treated and nontreated eyes. Mean reduction of IOP in the treated eye was 2.5 mm of Hg, a reduction of 16.1%, with maximal reduction of 3.7 mm of Hg. Mean reduction of IOP in the nontreated eye was 1.4 mm of Hg, a reduction of 9.0%. The treated eye had reduced pupil diameter at 30 minutes after treatment, which persisted throughout the 12 hours of the study. Mean reduction of pupil diameter in the treated eye was 2.9 mm, a reduction of 34.1%. In addition, a contralateral effect on pupil diameter was seen in the nontreated eye, with mean reduction of 1.2 mm, a reduction of 14.1%. Topical administration of timolol maleate resulted in reduction of IOP and pupil diameter in treated and contralateral eyes, thus supporting the use of timolol for treatment of glaucoma in dogs. Miosis indicates possible beta-adrenergic inhibition or alpha-adrenergic activation of the sphincter muscle. beta-Adrenergic blockade would then result in miosis.
Asunto(s)
Perros/fisiología , Presión Intraocular/efectos de los fármacos , Pupila/efectos de los fármacos , Timolol/farmacología , Administración Tópica , Animales , Timolol/administración & dosificaciónRESUMEN
Effects of topical administration of a single dose of timolol maleate, a nonselective beta-adrenergic blocking agent, on intraocular pressure (IOP) and pupil diameter were evaluated in the normotensive eyes of 10 clinically normal cats over 12 hours. Mean (+/- SEM) normal IOP was 17.1 (+/- 1.1) mm of Hg and diurnal fluctuation was observed, with the highest IOP seen in the evening. Mean (+/- SEM) normal pupil diameter was 10.1 (+/- 0.5) mm. Topical treatment with 0.5% timolol resulted in reduction of IOP in treated and nontreated eyes. This effect was time-dependent and was first observed at 6 hours after treatment. Mean reduction of IOP was 22.3% in the treated eye and 16.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction of pupil diameter was 38.7%. A contralateral effect on pupil diameter was not seen in the nontreated eye. Topical administration of timolol maleate results in a reduction of IOP in treated and contralateral eyes, which supports the use of timolol for treatment of glaucoma in cats. In addition, the treated eye becomes miotic. This effect may indicate beta-adrenergic inhibition or alpha-adrenergic activation of the iris sphincter muscle. beta-Adrenergic blockade would then result in miosis.
Asunto(s)
Gatos/fisiología , Presión Intraocular/efectos de los fármacos , Pupila/efectos de los fármacos , Timolol/farmacología , Administración Tópica , Animales , Enfermedades de los Gatos/inducido químicamente , Femenino , Masculino , Miosis/inducido químicamente , Miosis/veterinaria , Factores de Tiempo , Timolol/administración & dosificaciónRESUMEN
Effects of topical administration of a single dose of 2% pilocarpine on intraocular pressure (IOP) and pupil diameter were evaluated in normotensive eyes of 10 clinically normal cats over 12 hours. Mean (+/- SEM) normal IOP was 17.1 (+/- 1.1) mm of Hg and, diurnal fluctuation was observed, with the highest IOP seen in the evening. Mean (+/- SEM) normal pupil diameter was found to be 10.1 (+/- 0.5) mm. Topical treatment with pilocarpine resulted in reduction of IOP in treated and nontreated eyes. This effect was time-dependent and was first observed at 4 hours after treatment. Mean reduction of IOP was 15.2% in the treated eye and 9.3% in the nontreated eye. The treated eye had reduced pupil diameter at 30 minutes after treatment, and miosis persisted throughout the 12 hours of the study. Mean reduction in pupil diameter was 28.5% in the treated eye and 14.2% in the nontreated eye. Topically administered pilocarpine results in reduction of IOP and pupil diameter in treated and contralateral eyes, which supports the use of pilocarpine for treatment of glaucoma in cats.
Asunto(s)
Gatos/fisiología , Presión Intraocular/efectos de los fármacos , Pilocarpina/farmacología , Pupila/efectos de los fármacos , Administración Tópica , Animales , Enfermedades de los Gatos/inducido químicamente , Femenino , Masculino , Miosis/inducido químicamente , Miosis/veterinaria , Pilocarpina/administración & dosificación , Factores de TiempoAsunto(s)
Cirrosis Hepática Biliar/genética , Adolescente , Adulto , Femenino , Humanos , Cirrosis Hepática Biliar/patología , Masculino , Linaje , Puerto RicoRESUMEN
This discussion of normal and abnormal findings on routine ophthalmic examination of the foal should prove useful to the equine practitioner who must provide counsel to the concerned owner and/or breeder. Early diagnosis and treatment of ocular abnormalities improve the prognosis for continued function and aid determination of the significance of lesions observed in later life.
Asunto(s)
Animales Recién Nacidos , Oftalmopatías/veterinaria , Enfermedades de los Caballos/diagnóstico , Visión Ocular , Animales , Anoftalmos/veterinaria , Blefaritis/veterinaria , Catarata/veterinaria , Coriorretinitis/veterinaria , Coloboma/veterinaria , Enfermedades de la Conjuntiva/veterinaria , Conjuntivitis/veterinaria , Córnea/anomalías , Enfermedades de la Córnea/veterinaria , Opacidad de la Córnea/veterinaria , Quistes/veterinaria , Quiste Dermoide/veterinaria , Entropión/veterinaria , Anomalías del Ojo , Neoplasias del Ojo/veterinaria , Párpados/anomalías , Glaucoma/veterinaria , Caballos , Iris/anomalías , Enfermedades del Iris/veterinaria , Obstrucción del Conducto Lagrimal/veterinaria , Subluxación del Cristalino/veterinaria , Cristalino/anomalías , Microftalmía/veterinaria , Ceguera Nocturna/veterinaria , Enfermedades del Nervio Óptico/veterinaria , Desprendimiento de Retina/veterinaria , Enfermedades de la Retina/veterinaria , Hemorragia Retiniana/veterinaria , Estrabismo/veterinaria , Uveítis Anterior/veterinaria , Cuerpo Vítreo/anomalíasAsunto(s)
Enfermedades de los Caballos/congénito , Aparato Lagrimal/anomalías , Conducto Nasolagrimal/anomalías , Animales , Cateterismo/veterinaria , Femenino , Enfermedades de los Caballos/diagnóstico por imagen , Enfermedades de los Caballos/patología , Enfermedades de los Caballos/cirugía , Caballos , Masculino , Conducto Nasolagrimal/diagnóstico por imagen , Conducto Nasolagrimal/patología , Conducto Nasolagrimal/cirugía , RadiografíaRESUMEN
The anatomy of the nasolacrimal duct of the horse was studied grossly and radiographically, using barium contrast dacryocystorhinography and methyl methacrylate casts. Radiographic contrast studies were performed on 4 specimens and gross dissections were performed on 6 specimens. Dacryocystorhinography accurately delineated the course of the nasolacrimal duct, as was subsequently demonstrated by gross dissection. A 60% barium sulfate suspension produced good radiographic contrast, allowing critical assessment of the anatomic features of the nasolacrimal duct.
Asunto(s)
Caballos/anatomía & histología , Aparato Lagrimal/anatomía & histología , Animales , Enfermedades de los Caballos/diagnóstico por imagen , Enfermedades de los Caballos/patología , Aparato Lagrimal/diagnóstico por imagen , Enfermedades del Aparato Lagrimal/diagnóstico por imagen , Enfermedades del Aparato Lagrimal/patología , Enfermedades del Aparato Lagrimal/veterinaria , RadiografíaRESUMEN
A cyst involving the gland of the 3rd eyelid was removed from an 8-year-old dog. Clinically the circumscribed mass resembled a pigmented neoplasm. Histologically the cyst was multiloculated, with homogeneous eosinophilic periodic acid-Schiff-positive content. Melanin pigment was present in epithelial cells and cystic lumens. Protective functions of the 3rd eyelid were retained following excisional biopsy.