FB2026_03 , released September 17, 2026
Aberration: Dmel\In(2LR)SM1
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General Information
Symbol
In(2LR)SM1
Species
D. melanogaster
Name
Inversion (2LR) Second Multiple
FlyBase ID
FBab0004815
Feature type
chromosomal_inversion
Computed Cytological Breakpoints (relative to progenitor)

22A3-22B1;60B-60C

Sequenced Breakpoints (relative to progenitor)
2L:1,586,840..1,586,840 (In(2LR)SM1:bk1)
(Miller et al., 2018)
2R:24,117,046..24,117,046 (In(2LR)SM1:bk2)
(Miller et al., 2018)
Member of large scale dataset(s)
Nature of Aberration
Cytological Order

2Lt - 22A3 | 60B - 58B1 | 42A3 - 58A4 | 42A2 - 34A1 | 22D2 - 33F5 | 22D1 - 22B1 | 60C - 2Rt

Progenitor
In(2R)Cy
In(2L)Cy
Mutagen
X ray
Class of aberration (relative to wild type)
chromosomal_inversion
(FlyBase, 2007)
Class of aberration (relative to progenitor)
chromosomal_inversion
(Welshons, 1974)
Cytological Breakpoints (relative to progenitor)

22A3-22B1;60B-60C

(Welshons, 1974)
Causes alleles
hafSM1
(Miller et al., 2018)
nisSM1
(Miller et al., 2018)
CG3257SM1
(Miller et al., 2018)
Carries alleles
Transposon Insertions
Formalized genetic data

S << bk1 << bk2 << Pin

Genetic mapping information
Comments

The 5' (distal) end of this breakpoint corresponds to 2L:1 ,586,840 and the 3' (proximal) end corresponds to 2L:1 ,586,845 (release 6 coordinates), meaning that 4bp of genomic sequence is deleted at this breakpoint.

(Miller et al., 2018)

The 5' (proximal) end of this breakpoint corresponds to 2R:24 ,117,046 and the 3' (distal) end corresponds to 2R:24 ,117,059 (release 6 coordinates), meaning that 12bp of genomic sequence is deleted at this breakpoint.

(Miller et al., 2018)
Comments on Cytology

All limits from polytene analysis (FBrf0026367)

Sequence Crossreferences
DDBJ / EMBL / GenBank
DNA sequence
Protein sequence
Gene Deletion and Duplication Data
Genes Deleted / Disrupted
Complementation Data
Completely deleted / disrupted
Partially deleted / disrupted
Molecular Data
Completely deleted
Partially deleted
CG3257
(Miller et al., 2018)
haf
(Miller et al., 2018)
nis
(Miller et al., 2018)
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

    This chromosome enhances PEV.

    (Talbert et al., 1994)

    Homozygous lethal. Viability and fertility of heterozygote excellent.

    (Lindsley and Zimm, 1992)
    Stocks (0)
    Notes on Origin
    Discoverer
     

    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).

    (Parks and Cook, 2026.8.6)
    Balancer / Genotype Variants of the Aberration
    Separable Components
    Other Comments
     

    The pericentric inversion, In(2LR)22A3-B1;60B-C, enhances balancing power of In(2L)Cy + In(2R)Cy since it causes the single crossover between the two Cy inversions to yield complementary products that are dominant lethal. Heterozygote shows interchromosomal effect; used to increase crossing-over and gene conversion in ry region (Chovnick, Ballantine and Holm, 1971, Genetics 69: 179-209); also causes non-disjunction of compound autosomes (Lindsley and Grell, 1969).

    Synonyms and Secondary IDs (3)
    Reported As
    Symbol Synonym
    In(2LR)SM1
    (Miller et al., 2018)
    SM1
    (Parks and Cook, 2026.8.6)
    Name Synonyms
    Inversion (2LR) Second Multiple
    Secondary FlyBase IDs
      References (23)