Descriptive comments are included for all balancers with unique breakpoints. Variant comments are included only for selected variants. X Chromosome Balancers ====================== Basc ---- Description: Consists of two inversions, In(1)scS1Lsc8R and In(1)S (the two together have been called In(1)scS1Lsc8R+S) (FBrf0007148). In(1)scS1Lsc8R carries two copies of mutated sc resulting in mutant sc phenotypes (FBrf0007148, see FBrf0238387). Variant comment: Basc variants exist carrying different markers. The following is a list of the most commonly used variants and their markers: asc sc8 scS1 wa Bascy y82 sc8 scS1 wa Bar1 FM1 --- Description: Consists of two inversions, In(1)sc8 (an inversion of 1B2-3;20F) and In(1)dl-49 (an inversion of 4D7-E1;11F2-4). The two together have been called In(1)sc8+dl-49. Variant comment: In(1)sc8 and In(1)dl-49 were independently recombined together at least three times with different markers present. One isolate was called FM1 ("FM1" is now used for all three recombinants). It has the markers y31d sc8 wa lzS Bar1. The other two independent isolates are listed here under their original symbols: FM0 y31d sc8 w1 vOf m2 f1 Bar1 (now called FM1, w1 lz+ vOf m2 f1) M6-ML y31d sc8 wa vOf f1 (now called FM1, lz+ vOf f1 Bar+) We note that an early publication (and subsequently Lindsley and Zimm, FBrf0066905) reported that FM0 carried cv1. As far as we know, FM0 never carried cv1. FM3 --- Description: Generated by R.F. Grell by X-ray inducing a bipartite inversion of 3E-F;16A-B and 16A-B;19F-20F on a chromosome carrying both In(1)sc8 (an inversion of 1B2-3;20F) and In(1)dl-49 (an inversion of 4D7-E1;11F2-4) (FBrf0066905). FM4 --- Description: Generated By R.F. Grell by X-ray inducing an inversion of 3C;4E-F on a chromosome carrying both In(1)sc8 (an inversion of 1B2-3;20F) and In(1)dl-49 (an inversion of 4D7-E1;11F2-4) (FBrf0066905). FM6 --- Description: Generated By R.F. Grell by X-ray inducing an inversion of 15D-E;20F on FM4 (FBrf0066905). FM7a ---- Description: FM7a was generated by John Merriam by recombining the Chromosome X balancer, FM6 (generated by inducing an inversion of 15D-E;20F by X-rays on FM4), with an X chromosome carrying In(1)sc8 (an inversion of 1B2-3;20F) and In(1)dl-49 (an inversion of 4D7-E1;11F2-4) (FBrf0237833). Variant comment: FM7a variants have been made carrying different markers. The following is a list of named variants and their core markers (FBrf0237833, FBrf0098438, FBrf0102818 and references therein): FM7b y31d sc8 wa lzs Bar1 FM7c y31d sc8 wa snX2 vOf g4 Bar1 FM7d y31d sc8 Bar1 FM7e y31d sc8 oc1 ptg1 Bar1 (also known as FM7d, oc1 ptg1) FM7f y93j sc8 oc1 ptg1 Bar1 (also known as FM7i w+) FM7g y31d sc8 wa oc1 ptg1 vOf Bar1 (also known as FM7d, wa oc1 ptg1 vOf) FM7h y31d sc8 w1 oc1 ptg1 Bar1 FM7i y93j sc8 w1 oc1 ptg1 Bar1 FM7j y93j sc8 w1 FM7k y31d sc8 snX2 Bar1 FM8 --- Description: CRISPR/Cas9 was used to generate an additional inversion in the FM7c variant of FM7a by cutting at ct (at 7B4 inside the 4E1-11F2 inversion) and w (at 3B6 inside the 4D7-1B3 inversion) (FBrf0255123). Insc ---- Description: Consists of two inversions, In(1)scS1Lsc8R and In(1)dl-49 (the two together have been called In(1)scS1Lsc8R+dl-49) (FBrf0066905). In(1)scS1Lsc8R carries two copies of mutated sc resulting in mutant sc phenotypes (FBrf0007148, see FBrf0238387). Variant comment: Insc variants have been made carrying different markers, most of which were assembled by Muller. The following is a list of the most commonly used variants and their core markers: Binsc sc8 scS1 Bar1 Binscy yc4 sc8 scS1 Bar1 Binsinscy yc4 sc8 scS1 w1 snX2 Bar1 Binsn sc8 scS1 snX2 Bar1 Inscy yc4 sc8 scS1 winscy yc4 sc8 scS1 w1 Chromosome 2 Balancers ====================== CyO --- Description: CyO (also known as In(2LR)CyO or In(2LR)O) consists of a 2LR inversion of 30E-F;50C10-D1 (this single inversion event has also been called In(2LR)O) superimposed on In(2L)Cy (22D1-2;33F5-34A1) and In(2R)Cy (42A2-3;58A4). CyO-Df(2R)B80 ------------- Description: CyO-Df(2R)B80 was generated by recombination between the region of CyO distal to the 58B breakpoint and Ts(Y;2Lt)B80. The result was a CyO chromosome in which the 2R tip from 60F2 to 2Rt was replaced by a segment of YS and the X tip (1Lt to 1B2-3) carrying y+ (FBrf0068521, FBrf0053201). Df(2R)B80 disrupts Kr (FBrf0104713). CyO-Df(2R)B80 is a much better balancer for distal 2R genes that are still proximal to 60F2 (like Kr) than plain CyO. CyO, Tp(2;2)pk-sple26 ----------------------- Description: Generated by D. Coulson. Four X-ray induced breakpoints at 29F, 42F, 45A and 58E in CyO resulted in the rearrangement of three chromosomal segments that spanned CyO breakpoints in a way that resembles two transposition events. SM1 --- Description: An X-ray induced inversion of 22A3-B1;60B-C imposed on a chromosome carrying In(2L)Cy (22D1-2;33F5-34A1) and In(2R)Cy (42A2-3;58A4) (FBrf0066905). SM5 --- Description: Irradiation of SM1 resulted in transpositions and additional inversions on the SM1 chromosome. Two regions are duplicated on the chromosome: 2R:6 ,012,459-6,916,8092 (predicted cytology - 42A7-42E1) and 2R:21 ,972,072-22,689,962 (predicted cytology - 58A4-59A2). The distal duplicated segment allows deficiencies for the haploinsufficient gene RpS24 to be maintained as simple balanced stocks (FBrf0205398). SM6 --- Description: SM6 is an umbrella term for SM6a and SM6b, which were generated independently but in identical ways. Both were made by recombination between CyO (a 2LR inversion of 30E-F;50C10-D1 superimposed on In(2L)Cy (22D1-2;33F5-34A1) and In(2R)Cy (42A2-3;58A4) and SM1 (a 2LR inversion of 22A3-B1;60B-C superimposed on In(2L)Cy and In(2R)Cy). Variant comment: SM6a and SM6b variants carry slightly different marker sets. The following is a list of known SM6 variants and their markers: SM6a al2 DuoxCy dpylvI cn2P speck2 SM6b al2 DuoxCy amosRoi-1 dpylvI cn2P speck2 SM6#16 Ab(2)SM6#16, al2 DuoxCy dpylvI cn2P speck2 - X-ray derivative of SM6a, presumably has additional aberrations. Chromosome 3 Balancers ====================== DcxF ---- Description: An inversion on 3L of 62;67 was superimposed on the In(3LR)CxD chromosome carrying three inversions: 1) In(3L)D (69D3-E1;70C13-D1), 2) an inversion of 71F;85C, and 3) a three-breakpoint inversion (80;84A;93F - seen as two inversions of 80;84A and 84A;93 imposed on the 71F;85C inversion). In(3L)P and In(3R)P ------------------- Comment: In(3L)P (63B8-9;72E1-2) and In(3R)P (89C2-3;96A18-19) are found on the same chromosome in natural populations. At least three symbols have been given to this combination of inversions: C(3)x (no additional markers; also known as In(3LR)C3x or just C3x) LVM l(3)LVML1 pe1 l(3)LVMR1 PoLVM Payne (no additional markers) MRS --- Description: Consists of Tp(3;3)MRS, a transposition of 92E-93C and 87F1-92E into 71B2-71C2 (FBrf0033210). It likely carries M(3)76A1, a recessive lethal mutation that has produced weak, dominant Minute phenotypes in the past, but existing stocks have no discernable dominant Minute phenotypes. Variant comment: MKRS is a commonly used variant of MRS carrying the following markers: M(3)76A1 kar1 ry2 Sb1 TM1 --- Description: The progenitor to TM1, Tp(2;3)Me, was generated by X-raying an In(3L)P (63C;72E1-2) chromosome bearing Me1. Two inversions were introduced (89B;97D followed by 69E;91C) and a segment (59D3 to 60F) was removed from chromosome 2 and inserted into chromosome 3 in the 80 to 81 region. TM1 was then derived from the Dp(2;3) segregant of Tp(2;3)Me by double crossover with a normal-sequence third chromosome bearing kniri-1 to remove the transposed second chromosome segment and simultaneously introduce kniri-1 (FBrf0007382). TM2 --- Description: X-rays were used to induce five breakpoints on Chromosome 3 at 61A-C;74;89E1-2;93B;96A. TM3 --- Description: Multiple rounds of X-raying were used to add three inversions, 71C;94D-F, 76C;93A, and 79E;100C to a chromosome already carrying two inversions, In(3LR)sep (65D2-3;85F2-4) and In(3R)C (92D1-E1;100F2-3) (FBrf0013161, FBrf0232806). The original TM3 also carried a small translocation that replaced the tip of 3L with the tip of X, including the wildtype y gene (FBrf0013161). However, most TM3 chromosomes today carry a normal 3L tip due to crossovers between TM3 and non-balancer chromosomes (FBrf0232806). Note that the 94D breakpoint disrupts p53 (FBrf0232806, FBrf0247151) TM6 --- Description: TM6 was generated via X-ray induction of In(3LR)M6 (75C;94A) on a chromosome carrying three inversions: In(3LR)P88 (61A;89CD), In(3L)P (63C;72E1-2) and In(3R)C (92D1-E1;100F2-3) (FBrf0232806). There was a female-sterile mutation near the distal end of the e4-marked In(3R)C chromosome used as the progenitor to TM6 (FBrf0000690, FBrf0000910, FBrf0001261); consequently, deficiencies removing a region within 92F cannot be maintained over TM6 or most balancers derived from it. TM6B ---- Description: TM6B was generated by recombining TM6 with a chromosome carrying In(3LR)HR33 (61A1-2;87B) and inside it, In(3R)Hu (breaks in 84B1;84F2;86C7-8 resulting in the following order left to right inside In(3LR)HR33: 61A1-86C8|84F2-86C7|84B2-84F2|84B2-61A2). The recombination resulted in the replacement of the left end of In(3LR)P88 with the left end of In(3LR)HR33 including In(3R)Hu. The right breakpoint of In(3LR)P88 (order 89C4|61A2) was replaced with the right breakpoint of In(3LR)HR33 (order 87B4|61A2) by double crossover to compensate for the deficiency created by introducing the left end of In(3LR)HR33. Early TM6B versions usually included D3 or Tb1, also introduced by double crossover (FBrf0063387, FBrf0232806). In most stocks today, TM6B is marked with Tb1 or is derived from a TM6B chromosome that was previously marked with Tb1, but in which the Tb1 marker has since reverted or become suppressed. An unknown female sterile mutation was present near the distal end of In(3R)C in the progenitor TM6 chromosome; consequently, deficiencies removing a region within 92F cannot be maintained over TM3. TM6C ---- Description: Generated by recombining TM6 with a chromosome carrying In(3LR)HR33 (61A1-2;87B). The recombination resulted in the replacement of the left end of In(3LR)P88 with the left end of In(3LR)HR33. The right breakpoint of In(3LR)P88 (order 89C4|61A2) was then replaced with the right breakpoint of In(3LR)HR33 (order 87B4|61A2) by double crossover (FBrf0063387). An unknown female sterile mutation was present near the distal end of In(3R)C in the progenitor TM6 chromosome in region 92F, but it was probably removed by recombination with a In(3R)C lacking this mutation during the construction of TM6C since this balancer was originally homozygous viable and fertile. TM8 --- Description: X-rays were used to superimpose an inversion of 73F;87D2-3 on a chromosome carrying a dominant temperature sensitive lethal, l(3)DTS41, and two pre-existing inversions, In(3L)C90 (62D2-7;80C) and In(3R)C (92D1-E1;100F2-3) (FBrf0031278; FBrf0055684). TM9 --- Description: X-rays were used to superimpose two inversions, 76F;87A then 80C;85A, on a chromosome carrying the dominant temperature-sensitive lethal l(3)DTS41 and two pre-existing inversions, In(3L)C90 (62D2-7;80C) and In(3R)C (92D1-E1;100F2-3) (FBrf0031278; FBrf0055684). TMS --- Description: An inversion of 87A-B;97F-98A was superimposed on MRS (i.e., Tp(3;3)MRS) by Singson (FBrf0066905). Multiple Chromosomes Balancers ============================== T(2;3)A1-W ----------- Description: This is a spontaneous translocation that arose in a In(2L)Cy In(2R)Cy; TM2 stock (FBrf0017412, FBrf0066905). It carries a T(2;3) translocation (32;68) between a second chromosome carrying In(2L)Cy (22D1-2;33F5-34A1) and In(2R)Cy (42A2-3;58A4) and TM2 (61A-C;74;89E1-2;93B;96A). T(2;3)CyO-TM3-GFP ----------------- Description: Generated by X-ray induction of a translocation between CyO and TM3, each carrying both P{GAL4-Hsp70.PB} and P{UAS-GFP.Y} (FBrf0112022). The translocation breakpoints have not been reported. GFP expression is first seen in 10-12 hour old embryos. Expression is seen in many tissues during larval development but is strongest in salivary glands and the midgut. Expression can be seen without heatshock but can enhanced with heatshock (FBrf0112022). T(2;3)CyO-TM6B -------------- Description: A T(2;3) translocation between CyO and TM6B generated by E.H. Grell. The translocation breakpoints have not been reported. T(2;3)CyO-TM9 ------------- Description: X-rays were used to induce a T(2;3) translocation (59F;94A) between CyO and TM9 (FBrf0055684). T(Y;2)CyO --------- Description: Generated by X-ray induction of a Y;2 translocation between the Y chromosome and CyO, l(2)DTS5131 (a dominant temperature sensitive lethal allele). Can be used to construct "virginator" stocks since Cy males carry temperature-sensitive lethal. (FBrf0026034). When males are mated to wildtype females at room temperature, most male progeny have curly wings and most female progeny have wildtype (straight) wings. When progeny are reared from eggs at 30 degrees C, straight-winged female progeny live, but most if not all T(Y;2)CyO male progeny die. Any surviving straight-winged male progeny, which arise from nondisjunctional gametes, are sterile because they lack a Y chromosome. T(1;4)FM7-A ----------- Description: A translocation with breakpoints in the h26 or h27 region of the FM7a variant carrying P{Tb1}FM7-A and the right tip of chromosome 4. The result is that the left tip of FM7a, including the distal In(1)sc8 1B2;20F breakpoint and the bobbed rDNA locus, is appended to chromosome 4 (FBrf0262931), and the distal end of FM7a is replaced by the right tip of the fourth chromosome. The fourth chromosome breakpoint occurred distal to fourth chromosome genes, so no fourth chromosome genes are appended to the distal end of FM7a. T(1;4)FM7-A may be used the same way a typical X chromosome balancer is used for balancing X chromosomes - in fact it was used extensively as a routine X chromosome balancer before the translocation was discovered. Nevertheless, care must be exercised in using this balancer in crosses involving fourth chromosome genetic elements. T(2;3)SM2 --------- Description: X-rays were used to impose a translocation with breakpoints 21A;40F;80-81 on SM1 (FBrf0066905). FBrf0066905 notes that 40F and 80-81 breakpoints have not been determined relative to the centromeres. The final order of the chromosome segments has not been reported. T(2;3)SM6a-TM6B --------------- Description: Composed of a translocation between SM6a and TM6B (FBrf0109303). The translocation breakpoints have not been reported. T(Y;3)TMS --------- Description: Composed of a translocation between the Y chromosome and TMS. The translocation breakpoints have not been reported. T(2;3)TSTL ---------- Description: A T(2;3) translocation between CyO and TM6B (FBrf0092704). The translocation breakpoints have not been reported. T(2;3)TSTL14 ------------ Description: A T(2;3) translocation between SM5 and TM6B (FBrf0054636). The translocation breakpoints have not been reported. T(2;3)apXa ------------ Description: X-rays were used to induce a reciprocal translocation (41F;89E8-F1) between In(2R)Cy (42A2-3;58A4) and In(3R)P (89C2-3;96A18-19). The 41F breakpoint ( 2R:5375319 ) is just upstream of the ap-RXa wing enhancer resulting in dominant ap phenotypes (FBrf0228676). Effective as a balancer for medial regions of 2R and 3R, but it does not effectively balance 2L, 3L or the distal ends of 2R and 3R.
