chromosome yield Dennis_Young at
Tue Nov 8 13:38:00 EST 1994

> Kris Weber writes:
I have a quick question regarding chromosome yield.  If I need to finish after
sorting with 60 million chromosomes, how many cells must I start my isolation
prep with?  IE, How many cells must I grow?  These are human X chromosomes.

Thank you

Kris Weber
>The formulae I use on our FACStarPLUS to calculate sort rate & "expected" 
recovery (in a spread sheet) are:

R = (ma)*exp(-mnT)

where R = sort rate
        m = flow rate
        a = percent positive
        n = number of drops deflected
        T = 1/Period (@40 microseconds with a 70 micron nozzle)
        exp = exponent ( 10^(-mnT) will work too)
"Expected" recovery is

        P = exp(-(-1-a)uTn)

where u = frequency

At 1,200 chromosomes/s, 1% pure, 2 drops, frequency of 25,000; sort rate will be
@ 10/s with 14% recovery.
You'd need to start with over 4 x 10^8 cells!!!

I should also mention that I've only sorted whole cells!


*                                                                           *
* Dennis J. Young                         Voice : (619) 543-3928            *
* Flow Cytometry Core Facility            FAX   : (619) 543-7487            *
* University of California, San Diego     e-mail: djyoung at          *

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