Abstract: The present invention relates to a method for selecting a DNA sample comprising genomic DNA suitable for genotyping, comprising the steps of: i) pre-genotyping said genomic DNA using a set of polymorphic markers; ii) determining out of said set of polymorphic markers the percentage of polymorphic markers for which said genomic DNA is homozygous; and iii) selecting said DNA sample when said genomic DNA is homozygous for less than 70% of said set of polymorphic markers. Furthermore, a method of genotyping comprising a step of using a DNA sample selected by the method in accordance with the present invention and/or a step of applying the method provided herein is disclosed. The present invention also relates to a method for identifying a gene or a locus on a genome, said method comprising a step of using a DNA sample selected by the method provided herein and a step of applying the method described herein.