question on genotype

[poloke]

Dear all,

Anyone here who can tell me what this means (part of a genotype of a yeast): his3Δ1/his3Δ1 leu2Δ0/leu2Δ0

I have always been told that Δ before a gene, means that the gene is gone (knock out mutant).

But what does it mean if it stands at the end (his3Δ) or as in my other example: his3Δ1/his3Δ1 , What does that 1 mean?

I also do not get it why they put his3Δ1/his3Δ1 rather then just his3Δ1 ?

The only thing that comes up in my mind is that they are talking about alleles? Meaning: his3Δ1 , just 1 allele is mutated while his3Δ1/ his3Δ1 means that both alles are mutated?

[JackBean]

My guess would be, that the 1 in the end means first exon which is deleted, hence Δ. And yes, they probably write it twice because the yeast is diploid.