Ming, I'm preparing to order genetically engineered mice. For background strain selection, what's the difference between C57BL/6N and C57BL/6J? Actually, B6N and B6J share 99% identical gene sequences, and they are interchangeable for most experiments, with only minor sequence differences. Let's explore this in detail.

Ming, how do I design primers for qPCR? Primer design is a crucial step for successful qPCR experiments. The National Center for Biotechnology Information (NCBI) website (https://www.ncbi.nlm.nih.gov/) is a great tool for this purpose.

Ming, what's the difference between conventional KI mice and Rosa26/H11 KI mice? First, let's understand the genomic locations of Rosa26 and H11. Rosa26 is located on mouse chromosome 6 (human homologous locus is on chromosome 3p25.3), while H11 is located on mouse chromosome 11 (human homologous locus is on chromosome 17q21.31).

Ming, the experiment needs a large batch of offspring that are close in age. Is there a way to obtain them quickly? In this case, we can consider rapid colony expansion via IVF. Let's discuss IVF.

Ming, we have a batch of experimental mice that need to be preserved. Could you explain sperm cryopreservation? The principle of sperm cryopreservation is to lower or inhibit the metabolic activity of sperm through low-temperature treatment, thereby extending their preservation lifespan. After thawing, sperm retain a certain degree of motility and fertilization capacity. Let's delve into the details.