info:eu-repo/semantics/doctoralThesis
Detección de regiones genómicas implicadas en la determinación de sexo y crecimiento corporal en tilapia del Nilo (Oreochromis niloticus)
Detection of genomic regions involved in sex and body growth determination in Nile tilapia (Oreochromis niloticus)
Autor
Cáceres Cruz, Giovanna Patricia
Institución
Resumen
The Nile tilapia (Oreochromis niloticus) is one of the most cultivated and economically important species in world aquaculture. Intensive production promotes the use of monosex populations due to an important sexual dimorphism that favors the growth of the male compared to the female. In this way, Nile tilapia males show a higher growth rate. The identification of genomic regions associated with sex determination and growth in Nile tilapia is a research topic of great interest. The objective of this study was to identify genomic variants associated with sex determination, growth, and placement determination between them in three commercial populations of Nile tilapia. The complete genome sequencing of 326 individuals was performed, and a total of 2.4 million high-quality single nucleotide polymorphisms (SNPs) were identified. A genome-wide association study (GWAS) was able to identify markers associated with both traits. A logistic regression model for GWAS was used for sex determination, and a significant signal was identified comprising 36 SNPs, located in ligation group 23, spanning a genomic region of 536 kb. Ten of these 36 genetic variants intercept the gene of the antimüllerian hormone (Amh). While a mixed linear regression model was used to determine growth, six significant signals were detected for the entire genome comprising 15 SNPs, located on chromosomes 1, 7, 8, 9, 17, and 23. The most important genomic region for growth was located in ligament group 7 and explained 20% of the genetic variance for this trait. Additionally, we have placed genomic regions associated with both traits in LG23. This finding provides useful information to understand better the genetic mechanisms underlying sex determination and growth in Nile tilapia. El tercer y cuarto capítulo de la tesis esta siendo evaluado (paper) en una revista científica.