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. See 'Important Information for Marked Y chromosomes' below for more information.

Dp(1;Y)Bar[S] ("Bar-Stone Y") is a chromosome where an X segment carrying the dominant Bar[S] mutation has been swapped for the tip of the Y long arm.  See 'Important Information for Marked Y chromosomes' below for more information.

Dp(1;Y)Bar[S]Yy[+] has Bar[S] appended to the end of YL and y[+] appended to the end of YS. See 'Important Information for Marked Y chromosomes' below for more information.

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.

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 (see 'A chromosome carrying the mwh gene' below) 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.

One of the first uses of an attP-bearing Y chromosome 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".

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.