Subject: FlyBase query
Dear Dr. Henikoff,
I am curating your paper for FlyBase:
Talbert and Henikoff, 2000, Genetics 154(1): 259--272
and I have a question about the 'McT' stock.
This is the stock that is In(1)wmMc,wmMc
(<up></up> = superscript)
On page 267, you say that the 'McT chromosome is actually an X.YL
translocation with the point of exchange in the rDNA'.
At the moment FlyBase has that In(1)wmMc is an inversion with
breakpoints at 3C1-3C2 and 20F.
What I need to know is whether you think
1. that the X.YL translocation that is in your McT stock has occurred
'on top of' the original In(1)wmMc inversion
or
2. whether the original In(1)wmMc inversion was really a X.YL
translocation that had not been noticed before.
It makes a difference in FlyBase as to which is the case:
if you think 1. is true then I will make a new aberration in FlyBase,
called I guess T(1;Y)McT, with In(1)wmMc as the progenitor chromosome
if you think 2. is true then I will not make a new chromosome, but will
record that In(1)wmMc is actually a T(1;Y) (as well as the inversion)
and will correct the breakpoints in FlyBase.
I look forward to hearing from you,
Gillian
\--------------------------------------------------------------
Gillian Millburn.
FlyBase (Cambridge),
\--------------------------------------------------------------
>
Subject: Re: FlyBase query
Hi Gillian,
Our evidence favors 1. You'll notice that the wmMc attributable to Oster
(a student of Muller's) is just as described originally by Muller both
in being an In(1) and showing a variegating phenotype stronger than wm4.
The T(1;Y) that has been used in many labs and is the subject of other
papers that we refer to is just what we would have expected if during
stock maintenance an X;Y translocation had occurred on top of the In(1),
and we speculated that maintenance alone would favor such events:
X;Y translocations that occur between the X and Y rDNA happen frequently
(that's how you detach attached XXs) and because there may be a selective
advantage in suppressing the rst and/or other variegating phenotypes by
added heterochromatin (the bulk of the Y chromosome). Paul Talbert did this
work, and he can correct me if I'm in error on this. With respect to what
to call it, I suppose that 'McT' is appropriate, because that would work
whether or not you name it after Ken Tartof who first described the
phenotype or Paul Talbert who described the genotype.
Best regards,
\--Steve Henikoff
>
Subject: Re: FlyBase query
Gillian and Steve:
I missed the original question here, but let me try to make sure we're all
in agreement about which stock is which. The stock that behaves like
Muller's original description of In(1)wmMc is the In(1)wm4LwmMcR,v /
Df(YS)bb stock, which I called '4LMcR' in the paper. I received this stock
as Mid-America stock #1130. Probably this stock was generated by Muller
and is the basis of his claim that the left ends of In(1)wm4 and
In(1)wmMc can be exchanged without affecting their phenotypes. Muller
also reported that both reciprocal recombinants were bb+, and this is
consistent with the stock being kept over Df(YS)bb. The presumed
reciprocal recombinant, originally labeled In(1)wmMcLwm4R, f /
Df(YS)bb (Mid-America stock #1121 or my '4f') I found to have both ends of
wm4;  presumably Muller isolated a double recombinant moving f onto
In(1)wm4.
The original (non-recombinant, non-translocated) In(1)wmMc seems to have
been lost, although Art Hilliker and Tom Grigliatti both seem to have had
it in the 80s. Art told me his stock definitely did not have the T(1;Y). I
don't know whether Tom looked at the mitotic chromosomes of his stock, but
the stock used by Sinclair et al. (1989) behaves genetically like what I
expect for the original In(1)wmMc. Vett LLoyd told me that the
Grigliatti lab did not maintain this stock; the stock later used in the
Lloyd et al. 1997 paper was a different stock and behaves like the T(1;Y)
chromosome. Vett said they got the latter stock from another lab (she
wasn't sure which one). Probably her stock and Tartof's stock ('McT') both
derive from the stock that is now Bloomington stock #4478 ('McB'). This
stock was formerly a Mid-America stock from the Oster collection, i.e. it
was the original In(1)wmMc stock which must have acquired the T(1;Y)
prior to Tartof's report of it in 1984, probably around 1980 or so since
the untranslocated stock still existed in other labs during the 80s.
With respect to what
> to call it, I suppose that 'McT' is appropriate, because that would work
> whether or not you name it after Ken Tartof who first described the
> phenotype or Paul Talbert who described the genotype.
Shouldn't the proper name be something like 'X.YL, In(1)wmMc, wmMc'
or 'C(1;Y)1, In(1)wmMc, wmMc'?
Currently on Flybase C(1;Y)1 seems to cover this entire class of
translocations. Presumably any of them would have the same effect on
suppressing variegation, so naming this particular translocation based on
its effect on wmMc (such as 'T(1;Y)McT, In(1)wmMc, wmMc') seems
superfluous to me.
Paul Talbert
Fred Hutchinson Cancer Research Center
1100 Fairview Avenue N, A1-162
Seattle, WA 98109
>
Subject: Re: FlyBase query
Gillian:
	I think it should be clear from my previous message, but for
purposes of annotating Flybase, I believe the following information is
most likely to be true:
Rearrangement: 	In(1)wmMc
References: 	Muller 1946, DIS 20: 66-68
		Hilliker and Appels 1982, Chromosoma 86: 469-490.
		Sinclair et al. 1989, Mol. Gen. Genet. 216: 328-333.
Stocks:		None known.
Rearrangement:	In(1)wm4LwmMcR
References:	Muller 1946, DIS 20: 66-68
		Talbert and Henikoff 2000, Genetics  154:259-272 .
Stocks:		Henikoff lab
Rearrangement:  In(1)wmMcLwm4R
References:     Muller 1946, DIS 20: 66-68
Stocks:		None known
Rearrangement: 	C(1;Y)1, In(1)wmMc
References:	Tartof et al. 1984, Cell 37: 869-878.
		Locke et al. 1988, Genetics 120: 181-198.
		Tartof et al. 1989, Dev. Genet. 10: 162-176.
		Martin-Morris et al. 1997, Genetics 147: 671-677
		Lloyd et al. 1997, Genetics  145:945-959 .
		Talbert and Henikoff 2000, Genetics  154:259-272 .
Stocks:		Bloomington #4478
Rearrangements: C(1;Y)1, In(1)wmMcLwm4R and
		C(1;Y)1, In(1)wm4LwmMcR
References:	Lloyd et al. 1997, Genetics  145:945-959 .
Stocks:		None?
Paul Talbert
Fred Hutchinson Cancer Research Center
1100 Fairview Avenue N, A1-162
Seattle, WA 98109