Best Linear Unbiased Prediction
BLUP is a method for estimating the breeding value of animals that has found wide application in modern breeding and genetic projects in Europe and North America. This method was developed in the 50s by Charles Henderson, an American geneticist and professor at Cornell University. Since the late 70's - early 80's, with the development of science and improvement of computer technology, which allowed to quickly make complex statistical and mathematical calculations, the method began to be used in modern breeding practice.
The advantages of the BLUP method in animal breeding are obvious. It allows to obtain the most accurate breeding values on the basis of available data on the pedigree and performance of animals. Due to its mathematical approach and the use of multiple factors, BLUP takes into account both phenotypic and genetic information when estimating breeding value. This makes it more objective and reliable compared to other methods in breeding.
It is important to note that the establishment of a sustainably working conventional BLUP breeding value estimation is the foundation of any modern breeding and genetic project. Only after the conventional BLUP estimation is formed at the breeding farm, it is possible to move on to the next stage - genomic selection: GBLUP and Single Step GBLUP.
Genomic Best Linear Unbiased Prediction
The GBLUP method (Genomic Best Linear Unbiased Prediction) is the next stage in the development of conventional BLUP breeding value estimation. GBLUP is based on the use of genetic information obtained from the genome of animals (reference population).
GBLUP takes into account the genotypic data together with phenotype and pedigree information obtained from conventional BLUP estimation. This allows to obtain more refined breeding values and to increase the efficiency of selection.
Genomic breeding values can only be estimated with sufficient accuracy if SNP effects are calculated using a training sample with data from the own population.
Animals in the training sample should have conventional BLUP breeding values calculated on their own population and as close a genetic relationship as possible to the animals to be genotyped.
Breeding values from different countries are only applicable in the countries where they were estimated.
→ Thus, the breeding value estimation of a population is established only on the basis of its own breeding program with its own breeding goal, on its own data records.
Single Step Genomic Best Linear Unbiased Prediction
Single Step GBLUP is a further development of the conventional BLUP estimation and the GBLUP method. It includes more genetic data and allows a more accurate calculation of the breeding values.
What is needed to incorporate genomic selection (GBLUP and Single Step GBLUP)?
Is it cost-effective?
Single Step GBLUP
- It complements the conventional BLUP, if the conventional BLUP is implemented correctly!
- It is conventional pedigree BLUP with added information of genotypes
- It is very important that conventional BLUP is used correctly.
- Adding genotypes to use the Single Step GBLUP method is a small but expensive step. Therefore, it is necessary to focus on the establishment of the conventional BLUP-breeding value estimation, and to create an information database of genotypes under certain conditions.
- If conventional BLUP breeding value estimation is used correctly, it already leads to genetic progress.
- Thus, the main part of genetic progress is the result of the correct use of the conventional BLUP breeding value estimation!
Summarizing the above, we can come to a logical and only correct conclusion:
The modern way of implementing breeding and genetics projects
involves three successive stages of creating a information system: