PLSS HELP how is gene knockout similar to gene sequencing?

Gene knockout is a technique used to determine the function of a gene that has already been sequenced, which is achieved by analyzing the phenotype of the individual carrying the knockout mutation(s). Moreover, gene sequencing is a technique used to determine the sequence of a given gene, which allows to determine how gene variants (polymorphisms) may be associated with the phenotypes of the target trait.  

Explanation:

In genetics, gene knockout is a technique used to trigger mutations in a (already) sequenced gene in order to inactive its function and observe the resulting phenotype for a particular trait. This approach that starts with the inactivation of a given gene and ends with the phenotype is known as reverse-genetics. On the other hand, gene sequencing can be defined as the methodologies/techniques/tools used to determine the nucleotide base pair sequence of a particular gene. The gene knockout technique involves knowing a priori the gene sequence in order to obtain a gene knockout (gene KO). The combination of the information obtained from these techniques can be used to determine how variation (genetic variation) affects the expression of a phenotypic trait.

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