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General Information
Symbol
Dmel\Hmr2
Species
D. melanogaster
Name
FlyBase ID
FBal0144828
Feature type
allele
Associated gene
Associated Insertion(s)
Carried in Construct
Key Links
Allele class
Mutagen
    Nature of the Allele
    Allele class
    Mutagen
    Mutations Mapped to the Genome
     
    Type
    Location
    Additional Notes
    References
    Nucleotide change:

    G10594416A

    Amino acid change:

    E371K | Hmr-PB

    Reported amino acid change:

    E371K

    Comment:

    One of two amino acid changes in the HmrAB mutant. Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.

    Nucleotide change:

    G10593947C

    Amino acid change:

    G527A | Hmr-PB

    Reported amino acid change:

    G527A

    Comment:

    One of two amino acid changes in the HmrAB mutant. Site of nucleotide substitution in mutant inferred by FlyBase based on reported amino acid change.

    Associated Sequence Data
    DNA sequence
    Protein sequence
     
     
    Progenitor genotype
    Cytology
    Nature of the lesion
    Statement
    Reference

    Amino acid replacement: E371K. Amino acid replacement: G527A.

    Carried on aberration
    Expression Data
    Reporter Expression
    Additional Information
    Statement
    Reference
     
    Marker for
    Reflects expression of
    Reporter construct used in assay
    Human Disease Associations
    Disease Ontology (DO) Annotations
    Models Based on Experimental Evidence ( 0 )
    Disease
    Evidence
    References
    Modifiers Based on Experimental Evidence ( 0 )
    Disease
    Interaction
    References
    Comments on Models/Modifiers Based on Experimental Evidence ( 0 )
     
    Disease-implicated variant(s)
     
    Phenotypic Data
    Phenotypic Class
    Phenotype Manifest In
    Detailed Description
    Statement
    Reference

    Hmr2/HmrDf females have significantly reduced fertility compared to controls.

    Hmr2 suppresses hybrid male lethality of hybrid sons of crosses between D.melanogaster females and D.simulans males. This hybrid rescue is not suppressed if the hybrids also carry Dsim\Hmr+t8.6 or Dmau\Hmr+t9.4.

    The sterility of hybrid daughters of crosses between D.melanogaster females and D.simulans males is suppressed by Hmr2. This Hmr2-dependent rescue of hybrid female sterility is not affected if the hybrids also carry Dsim\Hmr+t8.6.

    Hmr2 can rescue to viability the hybrid male progeny of D.melanogaster females crossed to D.simulans males, but these hybrid males remain sterile and have rudimentary testes. Hmr2 can rescue the sterility of hybrid female progeny of D.melanogaster females crossed to D.simulans males. The degree of rescue of oogenesis depends on the D.simulans stock used, suggesting that D.simulans stocks are polymorphic for factors that allow rescue of the hybrids. No rescue of fertility is seen in female hybrids derived from Hmr2 D.melanogaster females crossed to D.simulans males of the C167.4 strain. However, hybrid females derived from the reciprocal cross (C167.4 D.simulans females mated to Hmr2 D.melanogaster males) do show rescue of fertility, suggesting that the genetic bases of fertility rescue in the two directions of crossing are at least partially distinct. Hybrid males derived from a cross of Hmr2 D.melanogaster females mated to D.mauritiana males are sterile and have rudimentary testes. Hmr2 can rescue the sterility of hybrid female progeny of D.melanogaster females crossed to D.mauritiana males. The degree of rescue of fertility depends on the D.mauritiana stock used. Little or no rescue of fertility is seen in female hybrids derived from Hmr2 D.melanogaster females crossed to D.sechellia males (10 D.sechellia stocks have been tested).

    Hybrid daughters (from a cross of D.melanogaster females to D.simulans or D.mauritiana males) that carry two D.melanogaster X chromosomes are lethal. This lethality is partially suppressed by one copy of D.melanogaster Hmr2.

    Crosses between D.simulans strain C167.4 females and D.melanogaster Hmr2 males result in hybrids of which females are fertile and males are sterile. The hybrid males have tiny atrophied testes containing no sperm and often have an abnormal abdomen phenotype. All the hybrid females in this cross typically produce eggs, although the degree of rescue of fertility is variable; some females contain only a few, very early stage egg clusters, while in other females oogenesis occurs normally in most cysts. There is a significant decrease in the quality and quantity of eggs and ovarioles containing germline cells as the hybrid females age. Eggs from older females may be ventralised.

    Crosses between D.simulans strain Tsimbazaza females and D.melanogaster Hmr2 males result in hybrids of which females and males are sterile. The hybrid males have tiny atrophied testes containing no sperm and often have an abnormal abdomen phenotype. A small number of females produce a few eggs (approximately 2 per ovary), although in most cases their ovaries are completely atrophied. The females contain germline cells, but they often have an unusual "doughnut" phenotype, with the germline cells being unusually large with a layer of smaller cells (likely to be follicle cells) surrounding each of the large cells. A large clump of DNA is visible inside the "doughnut" upon nuclear staining and looks like an aggregation of several large nuclei. Eggs may be ventralised.

    Crosses between D.simulans C167.4 or Tsimbazaza males and D.melanogaster Hmr2 females result in hybrids of which males that survive to adulthood often show a variety of somatic defects (including abnormal abdomens, notched wings, knobby wings and stumpy legs). The frequency of the defects varies with the parental D.simulans strain. Hybrid progeny are sterile, except for hybrid females from crosses involving C167.4 males; 41% of these females show some egg production, although they produce only approximately one egg per ovary and the eggs are small, ventralised or otherwise abnormal. Early stage egg clusters often show the germline cell "doughnut" phenotype.

    Hmr2 rescues the mitotic chromosome decondensation defect seen in the larval brain neuroblasts of male hybrids produced from a cross between D.melanogaster females and D.mauritiana males.

    Rare female hybrids from D.simulans strain C167.4 females and Hmr2 males have well developed ovaries that contain large number of mature eggs. The reciprocal cross fails to produce fertile female hybrids, indicating a maternal effect for the female sterility rescue (due to maternal contributions from the nuclear genome). No hybrid male sterility rescue is observed, males have rudimentary testes with no advanced stages of spermatogenesis. Lower levels of hybrid female fertility were also observed in crosses involving D.simulans strains Oxnard and vermilion to Hmr2.

    Rescues species hybrids that are normally inviable; rescues hybrid females from a cross of D.melanogaster Hmr2/Y males to sibling species females, as well as hybrid males from a cross of Hmr2 females to sibling species males.

    External Data
    Interactions
    Show genetic interaction network for Enhancers & Suppressors
    Phenotypic Class
    Phenotype Manifest In
    Additional Comments
    Genetic Interactions
    Statement
    Reference
    Xenogenetic Interactions
    Statement
    Reference
    Complementation and Rescue Data
    Comments
    Images (0)
    Mutant
    Wild-type
    Stocks (1)
    Notes on Origin
    Discoverer

    The In(1)AB chromosome carries a lesion in Hmr (Hmr2), which is responsible for the hybrid rescue associated with the chromosome.

    Comments
    Comments

    FBrf0051988 reported that the In(1)AB chromosome (which carries the Hmr2 allele) can prevent the larval lethality of hybrid males from crosses between D.simulans males and D.melanogaster females and the embryonic lethality of hybrid females from the reciprocal cross. A known Zhr[+] allele was recombined onto the In(1)AB chromosome, and the resulting chromosome can only prevent the hybrid male larval lethality, thus the two rescuing actions reported for the In(1)AB chromosome are not due to a single gene.

    FlyBase curator comment: It has been shown that the hybrid rescue associated with the In(1)AB chromosome is due to a lesion on the chromosome that affects Hmr function (Hmr2) and which is not associated with either inversion breakpoint (see FBrf0207733). Thus all information regarding hybrid rescue that had previously been reported in the literature for In(1)AB has been moved in FlyBase from the In(1)AB aberration report to the Hmr2 allele report.

    External Crossreferences and Linkouts ( 2 )
    Crossreferences
    GenBank Nucleotide - A collection of sequences from several sources, including GenBank, RefSeq, TPA, and PDB.
    GenBank Protein - A collection of sequences from several sources, including translations from annotated coding regions in GenBank, RefSeq and TPA, as well as records from SwissProt, PIR, PRF, and PDB.
    Synonyms and Secondary IDs (2)
    Reported As
    Name Synonyms
    Secondary FlyBase IDs
      References (14)