TAILIEUCHUNG - Báo cáo sinh học: " A note on the rationale for estimating genealogical coancestry from molecular markers"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học quốc tế đề tài: A note on the rationale for estimating genealogical coancestry from molecular markers | Toro et al. Genetics Selection Evolution 2011 43 27 http content 43 1 27 GSE Ge n et i cs Selection Evolution RESEARCH Open Access A note on the rationale for estimating genealogical coancestry from molecular markers Miguel Ángel Toro1 Luis Alberto García-Cortés2 and Andrés Legarra3 Abstract Background Genetic relatedness or similarity between individuals is a key concept in population quantitative and conservation genetics. When the pedigree of a population is available and assuming a founder population from which the genealogical records start genetic relatedness between individuals can be estimated by the coancestry coefficient. If pedigree data is lacking or incomplete estimation of the genetic similarity between individuals relies on molecular markers using either molecular coancestry or molecular covariance. Some relationships between genealogical and molecular coancestries and covariances have already been described in the literature. Methods We show how the expected values of the empirical measures of similarity based on molecular marker data are functions of the genealogical coancestry. From these formulas it is easy to derive estimators of genealogical coancestry from molecular data. We include variation of allelic frequencies in the estimators. Results The estimators are illustrated with simulated examples and with a real dataset from dairy cattle. In general estimators are accurate and only slightly biased. From the real data set estimators based on covariances are more compatible with genealogical coancestries than those based on molecular coancestries. A frequently used estimator based on the average of estimated coancestries produced inflated coancestries and numerical instability. The consequences of unknown gene frequencies in the founder population are briefly discussed along with alternatives to overcome this limitation. Conclusions Estimators of genealogical coancestry based on molecular data are easy to derive. Estimators .

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