Low rate of homologous recombinant clones - (Apr/15/2008 )

hi everybody

i am new to gene targeting and to the forum as well. I do gene targeting exp using mouse embyronic ES, G418 +ve and DT -ve selection. but the rate of homologous recombinant clones to the surviving clones is very low ~1:500. Does any one have any suggestion to increase the frequency?
If I posted the topic in the wrong forum plz notify me?

I think you would reselect a targeting vector for your work, low recombination rate is associated with the vector.
Good luck.

[quote name='Andy Fung' date='Apr 17 2008, 04:57 PM' post='132938']
I think you would reselect a targeting vector for your work, low recombination rate is associated with the vector.
Good luck.

Thanks Andy for advice,

I need to read something about how to design the targeting vector to give higher rate, does any one have sugesstions?

Also, I want to know the usual rate in others hands?