THIRD-CHROMOSOME BALANCERS

# C(3)x
 constitution:  In(3L)P In(3R)P.  (Probably not the same as
   Payne).
# LVM
 constitution:  In(3L)P In(3R)P, l(3)LVML pe l(3)LVMR.
 properties:  Homozygous lethal; suppresses crossing over in
   chromosome 3.
# MKRS
 constitution:  Tp(3;3)MKRS, M(3)76A, kar ry2 Sb.
 order:  61-71B2|92E-93C|87F1-92E|71C-87E8|93C-100.
 synthesis:  Chovnick.
 references:  1973, Genetics 76:  289-99.
   Hilliker, Clark, Chovnick, and Gelbart, 1980, Genetics
    95:  95-100.
 properties:  Homozygous lethal.  Suppresses crossing over in the
   proximal regions of both arms of chromosome 3.  Version lack-
   ing kar designated MRS.
# TM1:  Third Multiple 1
 constitution:  In(3LR)TM1, Me ri sbdl.
 order:  61-63|72E1-69E|91C-97D|89B-72E2|63C-
   69E|91C-89B|97D-100.
 synthesis:  Lewis.
 references:  1949, DIS 23:  92.
   Lewis and Mislove, 1953, DIS 27:  58.
   Shearn, 1974, Genetics 77:  115-25.
 properties:  Homozygous lethal; suppresses crossing over in
   chromosome 3.
# TM2
 constitution:  In(3LR)Ubx130, emc2 Ubx130 es.
 order:  61A|96A-93B|89D-74|61C-74|89E-
   93B|96A-100.
 synthesis:  Lewis.
 references:  1952, Proc Nat. Acad. Sci. USA 38:  953-61.
   1952, DIS 26:  66.
 properties:  Homozygous lethal.  Eliminates crossing over in
   chromosome 3 except at the end of the right arm.  Does not
   reliably balance mutations in the vicinity of ca.  MacIntyre
   and Wright (1966, DIS 41:  141-42) observed about 9% double
   crossing over in the unbroken segment of the left arm from 61C
   to 74 on the polytene map and 15% recombination between the
   breakpoint at 96A and ca in In(3LR)Ubx130, Ubx130 e/ru h th st
   cu sr es Pr ca females that were also heterozygous for an X-
   chromosome inversion behaving like In(1)sc8 and In(2LR)SM1; no
   recombination observed in other regions.  Some versions also
   carry pp.
# TM3
 constitution:  In(3LR)TM3, y+ ri pp sep l(3)89Aa bx34e e [not es
   according to Craymer (1980, DIS 55:  197-200)].  Some TM3
   stocks have lost y+ (Shearn, 1980, DIS 55:  167).
 order:  1A1-1A8|61A2-65E|85E-79E|100C-100F2|92D1-85E|65E-
   71C|94D-93A|76C-71C|94F-100C|79E-76C|93A-92E1|100F3-100F5.
 synthesis:  Lewis, 55g.
 references:  Mitchell, 1958, Cold Spring Harbor Symp. Quant.
    Biol. 23:  279-90.
   Lewis, 1960, DIS 34:  53-54.
   Tinderholt, 1960, DIS 34:  53-54.
 properties:  Stocks exist in which Ser or Sb and Ser are present
   in the balancer, making the TM3 chromosome homozygous lethal.
   With normal X and 2, all of chromosome 3 is effectively bal-
   anced; however, in the presence of FM6 and SM5, crossing over
   between y+ and ri (i.e., 61A2-65E) is appreciable.  Double
   crossovers that separate Sb or Ser from the inversion complex
   are rare, even in the presence of FM6 and SM5.
# TM6
 constitution:  In(3LR)TM6, HnP ssP88 bx34e UbxP15 e [UbxP15
   listed as Ubx67b in CP627 (Craymer, 1980, DIS 55:  197-200)].
 order:  61A|89C2-75C|94A-100F2|92D1-
   89C4|61A2-63B8|72E1-63B11|72E2-75C|94A-
   92E1|100F3-100F5.
 synthesis:  Lewis and Bacher, 66i.
 references:  CP627.
 properties:  Homozygous lethal.  Suppresses crossing over in
   chromosome 3.  Has unbroken regions with genetic lengths of
   approximately 10, 15, 20, and 30 units.
# TM6B
 constitution:  In(3LR)TM6B, Hu e.  Carries same inversions as
   TM6 except for substitution of In(3LR)HR33 for In(3LR)P88 and
   addition of In(3R)Hu.  Exists with several marker combina-
   tions, usually carrying D3 or Tb with various combinations of
   ca, h, and HnP.
 order:  61A1|87B2-86C6|84F1-86C5|84B6-
   84F1|84B3-75C|94A-100F2|92D1-87B4|61A2-
   63B8|72E1-63B11|72E2-75C|94A-92E1|100F3-
   100F5.
 synthesis:  Craymer.
 references:  1984, DIS 60:  234-36.
 properties:  Probably most efficient balancer of chromosome 3.
# TM6C
 constitution:  In(3LR)TM6C.  Carries same inversions as TM6B
   except that In(3R)Hu is absent.  Exists with various marker
   combinations (including cu and Sb) in addition to those listed
   for TM6B.
 order:  61A1|87B2-75C|94A-100F2|92D1-
   87B4|61A2-63B8|72E1-63B11|72E2-75C|94A-
   92E1|100F3-100F5.
 synthesis:  Craymer.
 references:  1984, DIS 60:  234-36.
 properties:  Homozygous viable, although homozygotes show lower
   viability and longer development time than wild type.  Resem-
   bles TM6B in balancing efficiency except that the absence of
   In(3R)Hu in TM6C lessens its effectiveness in the centromere
   region.
# TM8
 constitution:  In(3LR)TM8, l(3)DTS th st Sb e.
 origin:  X ray induced in In(3L)C90 In(3R)C, l(3)DTS4/+.
 synthesis:  Marsh.
 properties:  Effective chromosome 3 balancer that carries dom-
   inant temperature-sensitive lethal; shows very few viable and
   fertile escapers from the DTS phenotype.  87C-92D-E not bal-
   anced (Duncan).
# TM9
 constitution:  In(3LR)TM9, l(3)DTS th st Sb e.
 origin:  X ray induced in In(3L)C90 In(3R)C, l(3)DTS4/+.
 synthesis:  Marsh.
 properties:  Effective chromosome 3 balancer that carries dom-
   inant temperature-sensitive lethal; shows very few viable and
   fertile escapers from the DTS phenotype.  87A-92D-E not bal-
   anced (Duncan).
# winscy:  see In(1)scS1L sc8R + dl49