Current perspectives of the signaling pathways directing neural crest induction

The neural crest is a migratory population of embryonic cells with a tremendous potential to differentiate and contribute to nearly every organ system in the adult body. Over the past two decades, an incredible amount of research has given us a reasonable understanding of how these cells are generated. Neural crest induction involves the combinatorial input of multiple signaling pathways and transcription factors, and is thought to occur in two phases from gastrulation to neurulation. In the first phase, FGF and Wnt signaling induce NC progenitors at the border of the neural plate, activating the expression of members of the Msx, Pax, and Zic families, among others. In the second phase, BMP, Wnt, and Notch signaling maintain these progenitors and bring about the expression of definitive NC markers including Snail2, FoxD3, and Sox9/10. In recent years, additional signaling molecules and modulators of these pathways have been uncovered, creating an increasingly complex regulatory network. In this work, we provide a comprehensive review of the major signaling pathways that participate in neural crest induction, with a focus on recent developments and current perspectives. We provide a simplified model of early neural crest development and stress similarities and differences between four major model organisms: Xenopus, chick, zebrafish, and mouse

Hermaphroditism in two dogs - pathological and cytogenetic studies: a case report

A Pit-bull and a Beagle, both one-year-old, with complaints of an enlarged clitoris were clinically suspected for hermaphroditism. The enlarged clitoris, the uteri and the gonads were removed surgically from each animal and submitted to our department for histopathological evaluation. Tissue samples were fixed with 10% buffered formalin solution and processed routinely, after which paraffin sections were obtained and stained with H&E. A blood sample was taken from the Beagle dog and a peripheral lymphocyte culture was prepared. While the clitoris and uteri were confirmed histopathologically, the gonads were detected as a testis instead of an ovary for both dogs. Additionally, cytogenetic evaluation revealed a normal female chromosome complement, 78, XX for the Beagle dog. According to the gonadal and phenotypic sexes, both cases were first determined as 'male pseudohermaphroditism', a phenotypic sex disorder. However, after karyotyping analysis, we concluded that the 78, XX Beagle dog should be defined as suffering from XX sex reversal syndrome, a gonadal sex disorder

Hermaphroditism in two dogs – pathological and cytogenetic studies: a case report

A Pit-bull and a Beagle, both one-year-old, with complaints of an enlarged clitoris were clinically suspected for hermaphroditism. The enlarged clitoris, the uteri and the gonads were removed surgically from each animal and submitted to our department for histopathological evaluation. Tissue samples were fixed with 10% buffered formalin solution and processed routinely, after which paraffin sections were obtained and stained with H&E. A blood sample was taken from the Beagle dog and a peripheral lymphocyte culture was prepared. While the clitoris and uteri were confirmed histopathologically, the gonads were detected as a testis instead of an ovary for both dogs. Additionally, cytogenetic evaluation revealed a normal female chromosome complement, 78, XX for the Beagle dog. According to the gonadal and phenotypic sexes, both cases were first determined as 'male pseudohermaphroditism', a phenotypic sex disorder. However, after karyotyping analysis, we concluded that the 78, XX Beagle dog should be defined as suffering from XX sex reversal syndrome, a gonadal sex disorder

The association of genetic polymorphisms of bone formation genes with canine hip dysplasia

Background: Canine hip dysplasia (CHD) is an orthopedic disorder characterized by abnormal laxity of the hip joint. It is considered multifactorial and polygenic and affects predominantly medium and large sized dog breeds. Aims: The aim of this study was to identify CHD associated polymorphisms in chromosomal regions on CFA19, CFA24, CFA26, and CFA34. Methods: Blood samples from 60 dogs of different breeds were collected and genotyped, including 46 cases and 14 controls. After sequencing and single nucleotide polymorphism (SNP) determination of the target regions, an individual SNP analysis with a chi(2) statistic was performed based on the comparison of allele frequencies in cases and controls. Results: A significant association was observed between CHD and a T/C SNP on CFA19, which harbors genes involved in bone metabolism. No other significant association was found in the study and previously identified SNPs cannot be validated as related to CHD. Conclusion: Further research is warranted to identify CHD-associated polymorphisms in order to develop a genotype-based diagnosis and selection approach

Bifid phallus with complete duplication and a separate scrotum in a German shepherd dog: a case report

Diphallia or penile duplication is a rare congenital abnormality thought to result from duplication of the cloacal membrane in the early developmental stages in the uterus. The present case concerned a 4-year old intact male German shepherd dog. The patient presented with a complaint of paraphimosis. Clinical, laboratory, radiological and ultrasonographic examinations were carried out. Semen samples collected prior to surgery were examined. Following amputation, the penis with paraphimosis was sent for histopathological investigation. Karyotype analysis of the patient was also performed. As well as the first report of this abnormality in Turkey, this case report represents the first report of this condition in a German shepherd dog

Bifid phallus with complete duplication and a separate scrotum in a German shepherd dog: a case report

Diphallia or penile duplication is a rare congenital abnormality thought to result from duplication of the cloacal membrane in the early developmental stages in the uterus. The present case concerned a 4-year old intact male German shepherd dog. The patient presented with a complaint of paraphimosis. Clinical, laboratory, radiological and ultrasonographic examinations were carried out. Semen samples collected prior to surgery were examined. Following amputation, the penis with paraphimosis was sent for histopathological investigation. Karyotype analysis of the patient was also performed. As well as the first report of this abnormality in Turkey, this case report represents the first report of this condition in a German shepherd dog

Examination of Shape Variation of the Skull in British Shorthair, Scottish Fold, and Van Cats

A variety of skull shapes are frequently used for discrimination between animal species, breeds, and sexes. In this study, skulls of three different breeds of cats were examined by the geometric morphometric method, with the aim of revealing skull shape differences. For this purpose, 27 cats (6 British Shorthair, 7 Scottish Fold, and 14 Van cats) were used. The skulls of cats were modeled by computed tomography. Geometric morphometrics was applied using dorsal (8 landmarks, 63 semilandmarks) and lateral (8 landmarks, 63 semilandmarks) skull projections on these models. Centroid size differences between the breeds were statistically insignificant. However, the differences in shape were statistically significant for both the dorsal view and lateral view. Shape variation was less in the British Shorthair than in other breeds. Shape differences generally occurred around the orbit. In the skull of Scottish Folds, the orbit was situated more caudally than in other breeds. The British Shorthair had the largest orbital ring. In dorsal view, the Scottish Fold had the largest orbital diameter. The orbital ring of Van cats was smallest in both dorsal and lateral views. In the canonical variate analysis, it was seen that the breeds were separated from each other. The shape difference in the skull between different cat breeds could be revealed by geometric morphometrics. The results of this study provide useful information for taxonomy