I would like to know what is the maximum mating and sporulation efficiency for Saccharomyces cerevisiae. I have heard S288C isn't that great at sporulation. What strains are better? What is the maximum mating and maximum sporulation efficiency I might be able to achieve? If anyone could provide me links to references for this that would be great. Thanks!
Try Barack Cohen's lab for references on efficiency. I have seen 5-95% efficiency. Generally the less time the strain has spent in the lab, the better it will sporulate. Of the lab strains W303 has great efficiency and SK1 is the most synchronized.
Both mating and sporulation differs a lot between strains and strain combination. For sporulation efficiency - see PMID: 19840116 for a list. For mating, see e.g. PMID: 21261765. I am not sure that lab domestication has much to do with it. You find good and sporulators among natural strains, and good and bad sporulators among lab strains. As for most phenotypes, it has more to do with population structure. A few 1000 generations in the lab has little power to alter what billions of generations of selection and drift has established.
It really depends on the genetic background and the particular strains you are using. For example, W303 sporulates with great efficiency. I've seen up to 95%. BY background is far lower and I've seen under 5%. Also, specific mutations, like those involved in cell fusion (FUS mutants) or cell wall construction (mutants in glucan synthase, etc) can affect efficiencies.
SK1 back ground strain has higher, synchronized sporulation efficiency of about 98%. Also, it sporulates faster (24 hr) than normal wild-type strains W303, BY4743 (72-96 hr). But, the SK1 spores are not viable for longer time. After SK1, W303 strain offers good sporulation efficiency. I'm not aware about the mating efficiencies for these strains.
Since the previous posts haven't explicitly addressed mating: I used an old paper (PMID: 1097066) to optimize mating efficiency (measured as percentage of zygotes) and nothing was near 100%, but somewhat close. I have heard people talk about achieving 100% mating, but when considering the way they assayed success (selection for diploids) and how long they allowed mating to occur (overnight), I think it more likely that they got ~60% efficiency and then the diploids divided a few times to give an apparently higher efficiency. I've been told that if you micromanipulate two unbudded cells of opposite mating type into proximity, 100% will mate before either buds again, but I did this experiment once and did not get such high efficiency; more like 50%.
None of the preceding posts addressed sporulation conditions. If you simply use transfer to standard sporulation media (KAc with low supplementation), you may see much lower frequency than if you use a pre-sporulation medium for 24-48 hours first. For highest efficiency, incubation in liquid medium is apparently better than solid medium. Also, some strains can sporulate better on YPacetate than on standard sporulation medium. Temperature also can make a big difference to frequency. Here is a link to a nice web page at U. Washington for sporulation of different strains in different conditions: http://depts.washington.edu/younglab/yeastprotocols(htm)/strainsporulation.htm
Hi Xiao Yi
The easiest way I could think to do that is to make sure that you haploids have differ selectable markers. Grow the haploids in nicotinamide to rerepress the HM loci. The haploids will think they are diploid and downregulate haploid-specific genes. It's going to derepressed all silenced chromatin. Then wash out the nicotinamide and select for diploids. Or you could put the mating factors under a repressible promoter like the TET off that can induce transcription when you add tetracycline analog.
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