Special-purpose Y chromosomes
Updated January 7, 2016
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Introduction

Here we provide lists of stocks with Y chromosomes carrying visible markers or useful transgenes.

You should be careful in using marked Y chromosomes as a way to identify males. In Drosophila, X0 males arising from meiotic nondisjunction are not rare (roughly 1 in 2000 progeny). More importantly, XXY females are common in stocks and they transmit Y chromosomes to a large fraction of their female progeny.

Y chromosomes marked with y[+] and/or B[S]

Dp(1;Y)y[+] is a chromosome where the tip of the X including the yellow gene has been swapped for the tip of the Y short arm.

Dp(1;Y)B[S] ("Bar-Stone Y") is a chromosome where an X segment carrying the dominant B[S] mutation has been swapped for the tip of the Y long arm.

Dp(1;Y)B[S]Yy[+] has B[S] appended to the end of YL and y[+] appended to the end of YS.

Stocks with these three marked Y chromosomes are listed here.

Other potentially useful marked Y chromosomes

Dp(1;Y)y[+], Dp(1;Y)B[S] and Dp(1;Y)B[S]Yy[+] are the most commonly used Y chromosomes with visible markers and the duplicated chromosomal segments are particularly small. While it is somewhat uncommon for Y chromosomes carrying wild type alleles of other genes to be used to follow Y inheritance, Dp(1;Y)lz[+], Dp(1;Y)mal[+], Dp(2;Y)bw[+], Dp(1;2;Y)w[+] and other duplications have been used for this purpose. See Duplications for lists of stocks.

Y chromosome insertions of transgenes carrying the w, y and ry marker genes are listed here.

A Y chromosome carrying the mwh gene

One of the first uses of the attP-bearing Y above was to insert a wild type copy of the multiple wing hair gene. Induced or spontaneous somatic loss of this Y chromosome in a fly homozygous for mwh mutations on the third chromosome results in clones of wing cells with abnormal hairs. This method of assaying for chromosome loss during development is described in Szabad et al. (2012) "An assay to detect in vivo Y chromosome loss in Drosophila wing disc cells".

  Stk # Genotype
1 41459 w[1118]/Dp(2;Y)G, P{y[+t7.7] DiscRFP[DsRed2.3xP3]=mwh.+t38}attPY; mwh[1]

A Y chromosome expressing a fluorescent protein

The P{mwh.+t38} construct described above expresses DsRed from the 3xP3 promoter, which results in fluorescent photoreceptor cells in eyes, ocelli and Bolwig's organs. Its earliest expression is seen in late embryos in the nascent Bolwig's organs. The 3xP3 promoter can be ectopically activated in other tissues when transgenic constructs are inserted at some genomic sites, but, to our knowledge, the full DsRed expression pattern of the P{mwh.+t38}attPY insertion has not been explored.

Many people ask us for a Y chromosome carrying a transgene expressing a fluorescent protein to use in identifying male embryos. The Y chromosome carrying P{mwh.+t38}attPY is the only one we know about, but, unless it shows ectopic DsRed expression, it will not work for sorting younger embryos.

Even if a Y chromosome exists that provides early embryonic fluorescent protein expression, we would recommend against its use for identifying male embryos because it would also mark XXY females and it would fail to identify X0 males. A more accurate method for sexing embryos is to use a stock expressing GFP from the Sxl establishment promoter to identify females.

A Y chromosome carrying the "heat shock-hid" construct

P{hs-hid} expresses the apoptosis gene hid upon exposure to high temperature. In the stocks listed here, P{hs-hid} is inserted into the Dp(2;Y)G chromosome (see above). This chromosome provides a highly reliable way to kill males and recover only virgin female progeny. See Heat treatment method for P{hs-hid} stocks.

Stocks are listed here.