设计PCR引物时Tm温度有没有具体要求?比如说,Tm必须小于72度,或大于72度?

The best temperature for Taq polymerase is 72C. If your primer Tm is higher than 72C, then the polymerase would not work well, since the primer will not anneal to the template. If your primer Tm is lower than 50C, there are chances you would have non-specific bands. Therefore, in my experience, Tm for primers can be 50 to 70C, the best range is between 55 to 65.

PCR引物的Tm最好在55℃以上，以减少引物错配。一般以60℃~65℃左右为宜。

若按公式Tm= 4（G+C）+2（A+T）估计引物的Tm值，则有效引物的Tm为55~80℃，其Tm值最好接近72℃以使复性条件最佳。

Tm=2（A+T）+（C+G）