Why do I have to send samples again?

Because the quantity and quality of the extracted DNA have not fulfilled the basic standards required for the correct functioning of the PCR. This occurs more frequently with feathers since the quantity and quality of DNA that is found is variable, not only between species but within the same individual.

Remember, although you can extract DNA from the epithelial cells that remain in the barrel of the feather, it is the small drop of blood that is isolated and dried in the barrel of the feather where the largest quantity of DNA will be found. As a simple rule, it can be concluded that the larger the feather, the better the quality and the higher the amount of DNA  that will be extracted, thereby increasing the probability of PCR success in the laboratory. When the feathers that we receive are too small, or have been cut with scissors, or are dry and degraded, customers will be contacted to request the delivery of a new sample. To avoid further delay in the publication of our results, we will ask customers to resend samples of blood; this ensures a sufficient quantity and quality of DNA to carry out the analysis.