Caracterización del color de cuerpo, longitud de espina dorsal y porcentaje de reversión sexual en las generaciones F1 y retrocruce en Oreochromis niloticus
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Date
2024
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Universidad Nacional de Trujillo
Abstract
La investigación se orienta a la descripción de la variación fenotípica del color de cuerpo, longitud de la séptima espina dorsal y porcentaje de reversión sexual natural en las generaciones F1 y del retrocruce de la generación F1 con progenitores machos YY, en Oreochromis niloticus. Para lo cual, se cuenta con la generación F1 que provienen de la generación P1, constituida por machos rojos YY y hembras grises XX. Así también, la generación del retrocruce de neohembras XY (F1) con machos rojos YY (P1). Para la evaluación del color de cuerpo con la presencia de manchas grises en O. niloticus se estableció rangos de porcentajes que reflejan la magnitud de dichas manchas. Estos porcentajes se dividieron en rangos que van desde 0-5%, 6-30%, 31-50% y 51-100%. El porcentaje de reversión sexual natural, se estimó por la observación del sexo fenotípico, y evidenciado por los marcadores SCAR-PCR (sequence characterized amplified region) ligados a los cromosomas sexuales Y y X. Los resultados del trabajo indican que la coloración del cuerpo en las generaciones F1 y del retrocruce fue roja, con una menor magnitud de manchas grises en el cuerpo de la generación del retrocruce en comparación con la existente en la generación F1. En relación con la longitud de la séptima espina dorsal, se registró una media de 2.47 ± 0.45 cm en la F1 y de 3.49 ± 0.7 cm en la generación del retrocruce. Considerando el diseño de cruces antes mencionado, se esperaba en la F1 solo machos XY y en el retrocruce machos XY/YY. No obstante, se registró la presencia de neohembras como resultado de una reversión sexual natural, cuyos porcentajes fueron de 5.33 ± 2.31% en la F1 y de 9.33 ± 1.15% en el retrocruce. Con los marcadores moleculares SCAR-PCR se identificaron a las neohembras XY en F1 y neohembras XY/YY en el retrocruce, este último hallazgo es de importancia por contener genes de O. niloticus gris y genes de O. niloticus roja conformando su genotipo. Estas neohembras identificadas tanto en F1 como la del retrocruce quedan como material biológico en el Centro Experimental de Genética de la Facultad de Ciencias Biológicas de la Universidad Nacional de Trujillo para futuras investigaciones.
The research is aimed at describing the phenotypic variation in body color, length of the seventh dorsal spine and percentage of natural sexual reversal in the F1 generations and the backcrossing of the F1 generation with YY male parents, in Oreochromis niloticus. For this, there is the F1 generation that comes from the P1 generation, made up of YY red males and XX gray females. Likewise, the generation of backcrossing of XY neofemales (F1) with YY red males (P1). For the evaluation of body color with the presence of gray spots in O. niloticus, percentage ranges were established that reflect the magnitude of said spots. These percentages were divided into ranges ranging from 0-5%, 6-30%, 31-50% and 51-100%. The percentage of natural sexual reversal was estimated by the observation of phenotypic sex, and evidenced by the SCAR-PCR markers (sequence characterized amplified region) linked to the Y and the F1 and backcross generations was red, with a smaller magnitude of gray spots on the body of the backcross generation compared to that existing in the F1 generation. In relation to the length of the seventh dorsal spine, an average of 2.47 ± 0.45 cm was recorded in the F1 and 3.49 ± 0.7 cm in the backcross generation. Considering the aforementioned crossbreeding design, only XY males were expected in F1 and XY/YY males in the backcross. However, the presence of neofemales was recorded as a result of a natural sexual reversal, whose percentages were 5.33 ± 2.31% in the F1 and 9.33 ± 1.15% in the backcross. With SCAR-PCR molecular markers, XY neofemales were identified in F1 and These neofemales identified in both F1 and the backcross remain as biological material in the Experimental Genetics Center of the Faculty of Biological Sciences of the National University of Trujillo for future research.
The research is aimed at describing the phenotypic variation in body color, length of the seventh dorsal spine and percentage of natural sexual reversal in the F1 generations and the backcrossing of the F1 generation with YY male parents, in Oreochromis niloticus. For this, there is the F1 generation that comes from the P1 generation, made up of YY red males and XX gray females. Likewise, the generation of backcrossing of XY neofemales (F1) with YY red males (P1). For the evaluation of body color with the presence of gray spots in O. niloticus, percentage ranges were established that reflect the magnitude of said spots. These percentages were divided into ranges ranging from 0-5%, 6-30%, 31-50% and 51-100%. The percentage of natural sexual reversal was estimated by the observation of phenotypic sex, and evidenced by the SCAR-PCR markers (sequence characterized amplified region) linked to the Y and the F1 and backcross generations was red, with a smaller magnitude of gray spots on the body of the backcross generation compared to that existing in the F1 generation. In relation to the length of the seventh dorsal spine, an average of 2.47 ± 0.45 cm was recorded in the F1 and 3.49 ± 0.7 cm in the backcross generation. Considering the aforementioned crossbreeding design, only XY males were expected in F1 and XY/YY males in the backcross. However, the presence of neofemales was recorded as a result of a natural sexual reversal, whose percentages were 5.33 ± 2.31% in the F1 and 9.33 ± 1.15% in the backcross. With SCAR-PCR molecular markers, XY neofemales were identified in F1 and These neofemales identified in both F1 and the backcross remain as biological material in the Experimental Genetics Center of the Faculty of Biological Sciences of the National University of Trujillo for future research.
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Keywords
Tilapia, Oreochromis niloticus, reversión sexual natural, marcadores moleculares SCAR, color de cuerpo, séptima espina dorsal