Según los biólogos de Queensland el abalón de mas rápido crecimiento en el mundo, abalón oreja de burro Haliotis asinina, puede ser adecuado para la acuicultura. Además, esta especie se convierte en una alternativa de cultivo para los productores de camarón.

 

Los investigadores evaluaron si ellos podrían acelerar el crecimiento del abalón para la acuicultura, a través del uso de tecnología moderna para identificar y seleccionar genes que están activados en los animales que crecen mas rápido. Mediante la relación de genes específicos con altas tasas de crecimiento, ellos han demostrado que su propuesta es práctica.

“Si podemos seleccionar a los individuos que crecen rápido, nos da la oportunidad de tener el manual de instrucción genético adecuado, lo que asegura que su descendencia crecerá igual de rápido,” expresó Tim Lucas del Queensland Department of Primary Industries and Fisheries, quien trabajo con el Prof. Bernie Degnan de la Universidad de Queensland.

El trabajo ha demostrado que la tasa de crecimiento es altamente heredable. Los investigadores han desarrollado métodos para que en una simple prueba de sangre se mida la abundancia de los genes de rápido crecimiento en el abalón silvestre. Esto abre la posibilidad de preseleccionar los reproductores de mayor crecimiento, reduciendo de esta forma el nivel de genes indeseables desde el inicio.

“Usando esta técnica molecular para seleccionar individuos para el cultivo en vez de las tradicionales pruebas físicas, nosotros podemos cerrar un paso hacia las diferencias genéticas fundamentales que controlan la tasa de crecimiento,” dijo Tim.

Contacto:
Tim Lucas
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Resumen de la investigación:
The tropical abalone Haliotis asinina is a wild-caught and cultured species that is found throughout the Indo-Pacific. It is also an emerging model species for the study of growth, reproduction and development of haliotids and other vetigastropods.  H. asinina has the fastest recorded natural growth rate of any abalone and reaches sexual maturity within one year.  As such, it is a suitable abalone species for studying genetic and molecular aspects of commercially important traits such as growth. My thesis reports the analysis of growth and other traits in a single cohort of H. asinina that consisted of 84 families that were generated via a full-factorial mating design consisting of 14 sires and 6 dams.  Progeny were measured and then tested for parentage and RNA expression to explain the differences in size.  During this study a shell disease was discovered and investigated.
 
Estimating the amount of variation in size that is attributable to heritable genetic differences can assist the development of a selective breeding program. I estimated heritability for growth-related traits at 12 months of age in these 84
H. asinina families.  Of 500 progeny sampled, 465 were successfully assigned to their parents based on shared alleles at 5 polymorphic microsatellite loci.  Using an animal model, heritability estimates were 0.48 ± 0.15 for shell length, 0.38 ± 0.13 for shell width 0.36 ± 0.13 for weight.  Genetic correlations were > 0.98 between shell parameters and weight, indicating that breeding for weight gains could be successfully achieved by selecting for shell length.  A novel method for analysis of shell colour revealed that the proportion of blue in the shell was a very good indicator of shell length in this study.
 
Large and small abalone from the aforementioned experiment were compared for differences in RNA expression levels, using microarray gene expression profiling.  Comparing RNA from 3 large and 3 small pools of abalone each containing 4 individuals, the microarray experiment identified 14 genes were found to be significantly differentially regulated between fast and slow growers (p<0.05).  From this list and another list generated by the disease study, 7 genes were selected for further interrogation using qPCR.  This experiment aimed to compare gene expression for these 7 genes in fast and slow growing individuals.  Expression levels in different individuals revealed high levels of variation in expression levels between individuals, and that several of these genes have potential for use as markers for fast growth in aquaculture.  These include the genes ferritin, metallothionein and ribosomal protein L22.


Fuente: Science in Public