Heterogenous size

[Maria Cristina Costanzo]

In article <v01520d00acbc9906959a@[203.4.164.216]>,
germain at PETERMAC.UNIMELB.EDU.AU (Doris Germain) wrote:

> Hello everybody,
>         Let's say you stick out a strain for single colony on a plate. What
> would be your explanation (beside contamination of two strains) for
> heterogenous colony size on a plate?
> Thank you
> 
> Doris Germain
> Trescowthick Research Laboratories
> Peter MacCallum Cancer Institute
> Locked Bag 1
> A'Beckett Street
> Melbourne VIC 3000
> AUSTRALIA.

Dear Doris,

Many strains throw off spontaneous petites at high frequency - that is,
large deletions of the mitochondrial DNA occur. These so-called rho-
strains make smaller colonies than wild-type rho+ cells.  If this is the
case for your strain, then the larger colonies will be able to grow on
ethanol-glycerol medium, the smaller ones not.  Hope this helps -
Maria