FB2026_02 , released June 18, 2026
Aberration: Dmel\In(1)sc8
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General Information
Symbol
In(1)sc8
Species
D. melanogaster
Name
FlyBase ID
FBab0004197
Feature type
chromosomal_inversion
Also Known As
sc8
Computed Breakpoints include

1B2;h32

Sequence coordinates
X:382,384..382,384 (In(1)sc[8]:bk1)
(Miller et al., 2016)
X:21,368,973..23,542,271 (In(1)sc[8]:bk2)
(Miller et al., 2016)
Member of large scale dataset(s)
Nature of Aberration
Cytological Order
Progenitor
Mutagen
X ray
Class of aberration (relative to wild type)
chromosomal_inversion
(FlyBase, 2007)
Class of aberration (relative to progenitor)
chromosomal_inversion
(Belyaeva et al., 1998, Tower et al., 1993, Zhang and Spradling, 1993, Lindsley and Grell, 1968)
Breakpoints

1B2-1B3;20B-20D1

(Lindsley and Grell, 1968)

1B2-1B3;h32

(Belyaeva et al., 1998, Tower et al., 1993, Zhang and Spradling, 1993)
Causes alleles
sc8
(Golovnin et al., 2003, Gomez-Skarmeta et al., 1995, Campuzano and Modolell, 1992, Lindsley and Zimm, 1992, Dambly-Chaudiere and Ghysen, 1987, Campuzano et al., 1985)
CG32816sc-8
(Miller et al., 2016)
Carries alleles
Nopa33b
(Rice et al., 2015)
Transposon Insertions
Formalized genetic data

ac << bk1 << Zhr << bb << bk2

Genetic mapping information
Comments

The 5' (distal) end of this breakpoint corresponds to X:382 ,384 and the 3' (proximal) end corresponds to X:382 ,389 (release 6 coordinates). A 6-bp sequence (TTTCGT) from the ac-sc region is present at both breakpoint junctions, suggesting the inversion event created a small, staggered break at the euchromatic end. (FlyBase curator comment: coordinates updated from release 5 coordinates of X:276 ,417.. X:276 ,422 given in paper.)

(Miller et al., 2016)

This breakpoint is within the "1.688" satellite DNA repeat that covers approximately one-half of the X chromosome centric heterochromatin. A 6-bp sequence (TTTCGT) from the ac-sc region is present at both breakpoint junctions, suggesting the inversion event created a small, staggered break at the euchromatic end. (FlyBase curator comment: the coordinates used for this breakpoint correspond to the distal coordinate of the heterochromatin border defined in FlyBase (from FBrf0213099) through to the end of the sequenced chromosome.)

(Miller et al., 2016)

Breakpoint(s) molecularly mapped

(Ruiz-Gomez and Ghysen, 1993, Campuzano et al., 1985, Carramolino et al., 1982)

Left breakpoint between DNA coordinates 46.8 and 47.9 (Campuzano et al., 1985). 0 is an arbitrarily chosen EcoRI site in the scβ segment of ASC; positive values to the left (Carramolino, Ruiz-Gomez, Guererro, Campuzano and Modolell, 1982, EMBO J. 1: 1185-92).

Comments on Cytology

Left limit of break 1 from polytene analysis (FBrf0042024) Right limit of break 1 from complementation mapping against sc (FBrf0047940) Limits of break 2 from polytene analysis (FBrf0058564)

Sequence Crossreferences
DDBJ / EMBL / GenBank
DNA sequence
Protein sequence
AJ011702
AJ011703
AJ011704
L32746
L32747
Gene Deletion and Duplication Data
Genes Deleted / Disrupted
Complementation Data
Completely deleted / disrupted
sc
(Campuzano and Modolell, 1992, Campuzano et al., 1985)
Partially deleted / disrupted
Molecular Data
Completely deleted
Partially deleted
CG32816
(Miller et al., 2016)
Genes NOT Deleted / Disrupted
Complementation Data
 
Molecular Data
 
Genes Duplicated
Complementation Data
Completely duplicated
Partially duplicated
Molecular Data
Completely duplicated
Partially duplicated
Genes NOT Duplicated
Complementation Data
 
Molecular Data
 
Affected Genes Inferred by Location (0)
    If no genes are listed here, it may be because the affected region is very large. The JBrowse insert above may show an error for the same reason, and other FlyBase tools such as CytoSearch may also fail for large regions. You can contact FlyBase for more help.
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    Phenotypic Data
    In combination with other aberrations
    NOT in combination with other aberrations

    Mutants are viable and have normal bristle pigmentation.

    (Golovnin et al., 2003)

    Weak mutant for sc and shows a Hw effect. variegates for ac, y, and probably l(1)1Ac (Hess, 1962) in X0 male. Left break between ac and sc because induced deficiencies for the terminal uninverted portion of In(1)sc8 are deficient for y and ac but not sc8 (Patterson and Stone, 1935) and because In(1)sc8Lsc4R is deficient for sc (Sturtevant and Beadle, 1936); <up>i.e., for the α subdivision of the sc locus (Garcia-Bellido)</up>. Right break between bb and centromere because deficiencies for terminal genes are frequently deficient for bb (Patterson, 1933, Genetics 18: 32-52) as is In(1)sc4Lsc8R (Gershenson, 1933, J. Genet. 28: 297-313; Sturtevant and Beadle, 1936). In(1)sc8/+ female produces about 3% exceptional sons from 4-strand double crossing over within the inversion and about 8.7% recombination. In(1)sc8/+/Y female produces 19% secondary nondisjunction and 12% recombination (Sturtevant and Beadle, 1936; Grell, 1962, Genetics 47: 1737-54). In(1)sc8/0 partially male lethal (Baker, 1971; Johnson, Harger and Holm, 1979); variegates for y; ac enhanced.

    Stocks (308)
    Notes on Origin
    Discoverer

    Sidorov, 1929.

     
    Balancer / Genotype Variants of the Aberration
     
    Separable Components
     
    Other Comments
     

    "position-effect variegation for: l(1)1Ac" was stated as tentative.

    Synonyms and Secondary IDs (3)
    References (61)