Pith. sign in

REVIEW 3 major objections 6 minor 24 references

Genomic and pathological analyses of an asymmetric true hermaphroditism case in a female labrador retriever

T0 review · 3 major / 6 minor · reviewed 2026-08-10 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read A 78,XX hermaphrodite dog carries no causal DNA mutations, according to its whole-genome sequence.

desk verdict The case is striking, but the true hermaphroditism diagnosis is unsupported by the paper's own definition and the WGS negative result is built on post hoc filtering. read the letter →

arxiv 2501.02275 v1 pith:IPR4LNJB submitted 2025-01-04 q-bio.QM

Yihang Zhou This is my paper · ORCID
classification q-bio.QM
keywords hermaphroditismdisorderofsexualdevelopmentwholegenomesequencingatresiaanibladderduplicationcanineSRY-negativegenitalia
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

This paper reports a single labrador retriever with 78,XX chromosomes, no SRY gene, and asymmetric genitalia—a rudimentary penis, prepuce, and scrotum beside a vulva and vagina—along with an imperforate anus and a duplicated urinary bladder. The author argues that the dog is a case of true hermaphroditism, the first formally documented in this breed and the first asymmetric presentation in dogs. Whole-genome sequencing of male-specific, female-specific, and somatic tissues found no causal SNP in known sex-determination genes, leading the author to conclude the condition is unlikely to be genetic and probably results from errors in early developmental reprogramming. If correct, the case shows that a severe DSD phenotype in dogs can arise without a detectable DNA sequence change, and it argues for looking beyond the genome to epigenetic or developmental causes.

What carries the argument

The load-bearing analysis is a tissue-comparative whole-genome SNP screen: DNA from male-specific prepuce, female-specific vulva, and four somatic tissues was re-sequenced, aligned to the CanFam 3.1 reference, and variant-called to find mutations that appear only in one tissue type. The logic is that a genetic cause of the hermaphroditic phenotype should show up as a tissue-specific or high-impact variant, so the absence of any validated SNP after manual IGV inspection is taken as evidence against a sequence-level genetic cause. The paper also relies on the standard DSD classification scheme, which distinguishes true hermaphroditism (both ovarian and testicular tissue) from pseudohermaphroditism.

What would settle it

Re-examine the archived gonadal FFPE blocks: if histology shows two ovaries and no testicular or ovotestis tissue, then the case is not true hermaphroditism as defined, and the paper's central classification and its comparison with other true hermaphroditism cases collapse.

Watch

Extended reading notes

Core claim

On the paper's own terms, the central discovery is that a phenotypically hermaphroditic 78,XX SRY-negative dog carries no causative single-nucleotide variants: whole-genome resequencing at roughly 22–46× coverage generated about 1.7 million SNPs relative to the reference genome, but only 0.15% of genotypes differed between male-specific and female/somatic tissues, and manual inspection showed these to be mostly false positives, with no candidate changes in the known sex-development genes. The author therefore classifies the case as an asymmetric true hermaphroditism, with two normal ovaries on the female side and rudimentary male external genitalia, and concludes that the disorder is presumably due to errors in early developmental reprogramming rather than a straightforward genetic anomaly.

Load-bearing premise

The diagnosis of true hermaphroditism rests on the presence of both ovarian and testicular tissue, yet the report only documents two normal ovaries and does not describe testicular tissue anywhere.

Editorial extensions

If this is right

  • If the case is correctly classified, it extends the reported canine true hermaphroditism cases from 16 to 17 and adds the first labrador and the first asymmetric presentation.
  • The negative WGS result implies that a normal 78,XX female karyotype with no SRY can still produce male external genitalia through non-sequence mechanisms.
  • The findings suggest that standard karyotyping, PCR for SRY, and even whole-genome SNP analysis may miss the cause of some DSD cases, so complementary epigenetic or transcriptomic analyses are warranted.
  • The co-occurrence of hermaphroditism, Type 2 atresia ani, and sagittal bladder duplication in one dog points to a shared early developmental disruption rather than an isolated gonadal event.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • The paper's own evidence for 'true' hermaphroditism is incomplete: the female side has two normal ovaries, but no testicular tissue is histologically described, so if the gonads were both ovaries the case would instead be a female pseudohermaphroditism and the central conclusion would need reworking.
  • A testable extension is to probe the preserved FFPE tissues for DNA methylation or chromatin signatures at sex-determining loci, which could identify an epigenetic basis consistent with the 'reprogramming error' hypothesis.
  • The tissue-specific sequencing design could be pushed further with RNA-seq or methylation arrays on the same samples to catch regulatory changes that SNP calling cannot see.
  • If comparable asymmetric DSD cases in dogs are sequenced, a shared absence of coding variants would strengthen the developmental-error explanation, while a shared variant would overturn it.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. This manuscript reports a single case of a female Labrador retriever with 78,XX SRY-negative karyotype and asymmetric external genitalia, anal atresia, rectovaginal fistula, and sagittal bladder duplication. The authors performed karyotyping, SRY PCR, necropsy, and whole-genome resequencing of pooled FFPE tissue samples. They called SNPs, filtered them with manually determined QUAL and COV thresholds, and found no candidate causal SNPs in known sex-determination genes. They conclude that the condition is unlikely to be genetic and presumably results from errors in early developmental reprogramming. The paper claims to be the first whole-genome-based report of a DSD dog with a negative SNP finding.

Significance. If fully supported, the paper would be a notable single-case contribution: it applies whole-genome sequencing to a DSD dog and reports a negative SNP finding, and it documents an unusual combination of congenital malformations. The descriptive clinical and surgical details are of interest to veterinary practitioners. However, the central classification as true hermaphroditism is not supported by the presented pathology, and the negative genetic conclusion rests on a SNP-only analysis with post hoc filters and no orthogonal validation. The paper's main claims therefore currently exceed the evidence. The manuscript also lacks reproducible data or scripts, although it does provide some independent grounding through karyotyping and PCR.

major comments (3)
  1. [Introduction, Results, Discussion] The paper's own definition of XX true hermaphroditism requires the presence of both ovarian and testicular tissues. The Results describe 'two normal ovaries' on the female side and a rudimentary scrotum, penis, and prepuce on the male side, but no testicular parenchyma, seminiferous tubules, or Leydig cells are reported anywhere, and no histological figure or pathological description of testicular tissue is provided. If the gonads were both ovaries, this case would be a female pseudohermaphroditism or another XX DSD by the paper's own criteria, and the claimed novelty of 'asymmetric true hermaphroditism' would collapse. This is a load-bearing classification issue that must be resolved with explicit gonadal histology or immunohistochemistry before the central claim can be evaluated.
  2. [Materials and Methods, SNP calling and analyses; Results] The central negative claim—that no causal SNPs exist—is under-supported. The QUAL=500 and COV=6 thresholds were determined by manual IGV inspection after examining the calling results, which is a post hoc filtering procedure, and no independent validation (e.g., Sanger sequencing or a second caller) was performed. The analysis is restricted to SNPs; structural variants, copy number variants, and insertions/deletions were not assessed, despite their known role in DSD. The pooled FFPE tissue groups may also introduce artifacts, and coverage is modest (22–46×). Therefore, the statement in the Results that 'this result itself strongly indicates that this phenotype is not the result of any SNPs' is not justified; absence of SNPs in a small candidate set after post hoc filtering cannot support a genome-wide negative conclusion.
  3. [Discussion] The Discussion overinterprets the negative SNP finding. It states that the condition 'likely arose from epigenetic or embryologic processes rather than a straightforward genetic anomaly,' but the paper contains no epigenetic data and no analysis of non-coding regulatory variants, structural variants, or somatic mosaicism. The conclusion 'unlikely to be genetic' is therefore not a logical consequence of the analysis; it is an unsupported speculation presented as a result. This overreach is central to the paper's stated contribution and should be substantially qualified or removed.
minor comments (6)
  1. [Throughout] There are numerous typographical errors, including 'exterenal', 'threhold', 'Intergrative', 'refer allele', 'preuce', 'exsits', and 'PCGs' inconsistently used for 'PGCs'; these should be corrected.
  2. [References] The reference list is duplicated multiple times in the manuscript, and several in-text claims (e.g., '16 cases of true hermaphroditism reported in the literature') are not supported by a specific citation.
  3. [Results, first paragraph] The text states an incidence of Type 2 Atresia ani of '70 in 1,000,000 dogs' without a citation; this epidemiological claim needs a source.
  4. [Materials and Methods, Genomic DNA extractions from FFPE samples] The sentence 'Slides were cut from formalin-fixed paraffin-embedded (FFPE) samples of kidney' is incomplete; the listing of the seven samples and their grouping into somatic, female, and male tissues appears only in the next subsection and should be integrated.
  5. [Results, Genome coverage] The coverage value '46.3 in female-specific tissue' is missing the multiplication symbol and unit ('46.3×'); the same applies to other coverage values.
  6. [Methods, SNP calling] The manuscript states that 'self-written scripts' were used but provides no code or data availability statement; for reproducibility, scripts and accession numbers should be provided.

Circularity Check

1 steps flagged · score 2.0 of 10

Minor threshold-calibration circularity in the negative SNP finding; no load-bearing self-citation or definitional circularity.

  1. fitted input called prediction [Materials and Methods, 'SNP calling and analyses' (final paragraph)]
    "Despite that we could not identify SNPs causing the hermaphroditic phenotype, this result itself strongly indicates that this phenotype is not the result of any SNPs."

    The negative conclusion is presented as strong evidence, but it is a restatement of the filtered SNP call set. The QUAL=500 and COV=6 thresholds were determined by manually inspecting the same variant calls in IGV before filtering, so the absence of SNPs after filtering is not an independent prediction. Any real variant that fell below those hand-picked thresholds would be invisible to the subsequent analysis. The manual IGV inspection did independently identify concrete false positives, which prevents this from being a hard by-construction equivalence, but the conclusion is nonetheless partly an artifact of the filter-calibration step.

full rationale

This is a single-case whole-genome sequencing report rather than a formal derivation, so most circularity patterns do not apply. There are no load-bearing self-citations, no imported uniqueness theorem, and no renamed empirical pattern. The only potentially circular step is the SNP-negative conclusion: the QUAL and COV filtering thresholds were set by inspecting the same variant calls that were later filtered, and the paper then treats the absence of SNPs in that filtered set as strong evidence that the phenotype is not caused by SNPs. That is a modest circularity because the filter choice and the negative result share the same data source; however, the manual IGV inspection independently identified concrete false positives, so the negative finding is not forced by construction. The more serious problem with the paper is diagnostic rather than circular: it labels the case 'true hermaphroditism' while reporting 'two normal ovaries' and no testicular tissue, which contradicts its own definition requiring both ovarian and testicular tissue. That is a correctness and classification issue, not a circular derivation, and therefore is not scored as circularity here.

Assumptions & free parameters 2 free parameters · 4 assumptions · 0 invented entities

The paper introduces no fitted parameters beyond data-processing thresholds. It relies on the completeness of SNP-only analysis and on a diagnostic classification that is not supported by the reported gonadal histology. No new entities are postulated.

free parameters (2)
  • QUAL threshold = 500
    Set after manual IGV inspection to filter SNP calls; the negative conclusion depends on this threshold.
  • COV threshold = 6
    Set after manual IGV inspection to remove low-coverage calls; used to support the negative result.
assumptions (4)
  • ad hoc to paper SNP-only analysis of three pooled FFPE tissue groups can detect all relevant genetic causes of DSD.
    The paper concludes 'not the result of any SNPs' without analyzing structural variants, copy number, or regulatory variants, and without orthogonal validation.
  • ad hoc to paper Manual IGV inspection with QUAL>=500 and COV>=6 yields true variant calls.
    Thresholds and manual calls are used as ground truth; no sensitivity or specificity assessment is provided.
  • domain assumption CanFam 3.1 reference and GATK 3.8 pipeline are appropriate for FFPE canine WGS.
    Standard tools are used, but FFPE artifacts are known to inflate false positives; no mitigation besides filtering is described.
  • ad hoc to paper The case is correctly classified as true hermaphroditism.
    No testicular tissue is histologically documented; the text describes two normal ovaries and male external genitalia, which is more consistent with female pseudohermaphroditism.

how reviews work

0 comments
Cite this review

Pith. "Pith review of Genomic and pathological analyses of an asymmetric true hermaphroditism case in a female labrador retriever." pith.science (2026). https://pith.science/paper/IPR4LNJB

@misc{pith2026250102275,
  author       = {Pith},
  title        = {Pith review of: Genomic and pathological analyses of an asymmetric true hermaphroditism case in a female labrador retriever},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/IPR4LNJB}},
  note         = {Machine review of arXiv:2501.02275}
}
read the original abstract

The two main gonadal development disorders in dogs are true hermaphroditism and XX male syndrome. True hermaphroditism can be divided into two subcategories: XX sex reversal and XY sex reversal. XX Sry-negative sex reversal is more common, and it is characterized by the presence of both ovarian and testicular tissues in an animal. To date, there are 16 cases of true hermaphroditism reported in the literature, 15 of which are XX true hermaphroditism. Hermaphroditism has not been formally documented in labrador retrievers, and no case of asymmetric hermaphroditism has been reported in the literature.

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

24 extracted references · 24 canonical work pages

  1. [17]

    Animal reproduction science, 2021

    Szczerbal, I., et al., Chromosome abnormalities in dogs with disorders of sex development (DSD). Animal reproduction science, 2021. 230: p. 106771

    work page 2021

  2. [24]

    Sexual Development, 2012

    Meyers-Wallen, V., Gonadal and sex differentiation abnormalities of dogs and cats. Sexual Development, 2012. 6(1-3): p. 46-60. 16

    work page 2012

  3. [34]

    PloS one,

    Rudigier, L.J., et al., Ex vivo cultures combined with vivo-morpholino induced gene knockdown provide a system to assess the role of WT1 and GATA4 during gonad differentiation. PloS one,

    work page

  4. [35]

    Lin, Y.-T. and B. Capel, Cell fate commitment during mammalian sex determination. Current Opinion in Genetics & Development, 2015. 32: p. 144-152

    work page 2015

  5. [51]

    WNT4, RSPO1, and FOXL2 in sex development

    Biason-Lauber, A. WNT4, RSPO1, and FOXL2 in sex development. in Seminars in reproductive medicine. 2012. Thieme Medical Publishers

    work page 2012

  6. [61]

    Best Practice & Research Clinical Obstetrics & Gynaecology, 2018

    Witchel, S.F., Disorders of sex development. Best Practice & Research Clinical Obstetrics & Gynaecology, 2018. 48: p. 90-102

    work page 2018

  7. [62]

    Best practice & research Clinical endocrinology & metabolism, 2010

    Biason-Lauber, A., Control of sex development. Best practice & research Clinical endocrinology & metabolism, 2010. 24(2): p. 163-186

    work page 2010

  8. [63]

    Koopman, P., et al., Male development of chromosomally female mice transgenic for Sry. Nature,

    work page

Show all 24 references
  1. [64]

    351(6322): p. 117-121

  2. [65]

    Journal of Biochemistry,

    Kanai, Y., et al., From SRY to SOX9: Mammalian testis differentiation. Journal of Biochemistry,

  3. [66]

    Animal Reproduction Science, 2010

    Poth, T., et al., Disorders of sex development in the dog—adoption of a new nomenclature and reclassification of reported cases. Animal Reproduction Science, 2010. 121(3-4): p. 197-207

    2010

  4. [67]

    Sexual Development, 2012

    Meyers-Wallen, V., Gonadal and sex differentiation abnormalities of dogs and cats. Sexual Development, 2012. 6(1-3): p. 46-60

    2012

  5. [75]

    Best Pract Res Clin Endocrinol Metab, 2010

    Biason-Lauber, A., Control of sex development. Best Pract Res Clin Endocrinol Metab, 2010. 24(2): p. 163-86. 18

    2010

  6. [81]

    Vekemans, and C

    Malan, V., M. Vekemans, and C. Turleau, Chimera and other fertilization errors. Clinical genetics,

  7. [87]

    The Lancet, 2004

    Lanfranco, F., et al., Klinefelter's syndrome. The Lancet, 2004. 364(9430): p. 273-283

    2004

  8. [92]

    Orphanet journal of rare diseases, 2010

    Tartaglia, N.R., et al., A review of trisomy X (47, XXX). Orphanet journal of rare diseases, 2010. 5(1): p. 1-9

    2010

  9. [94]

    Sex Dev, 2008

    Chassot, A.A., et al., Genetics of ovarian differentiation: Rspo1, a major player. Sex Dev, 2008. 2(4-5): p. 219-27

    2008

  10. [96]

    Child and Adolescent Psychiatric Clinics of North America, 2007

    Kesler, S.R., Turner syndrome. Child and Adolescent Psychiatric Clinics of North America, 2007. 16(3): p. 709-722

    2007

  11. [98]

    Sex Dev, 2008

    Chassot, A.A., et al., Genetics of ovarian differentiation: Rspo1, a major player. Sex Dev, 2008. 2(4-5): p. 219-27. 19

    2008

  12. [99]

    DeFalco, T. and B. Capel, Gonad morphogenesis in vertebrates: divergent means to a convergent end. Annu Rev Cell Dev Biol, 2009. 25: p. 457-82

    2009

  13. [100]

    Best Pract Res Clin Endocrinol Metab, 2010

    Biason-Lauber, A., Control of sex development. Best Pract Res Clin Endocrinol Metab, 2010. 24(2): p. 163-86

    2010

  14. [101]

    Sex Dev, 2008

    Chassot, A.A., et al., Genetics of ovarian differentiation: Rspo1, a major player. Sex Dev, 2008. 2(4-5): p. 219-27. Biason-Lauber, A. (2010). Control of sex development. Best Pract Res Clin Endocrinol Metab, 24(2), 163-

    2010

  15. [186]

    A., Gregoire, E

    doi:10.1016/j.beem.2009.12.002 Chassot, A. A., Gregoire, E. P., Magliano, M., Lavery, R., & Chaboissier, M. C. (2008). Genetics of ovarian differentiation: Rspo1, a major player. Sex Dev, 2(4-5), 219-227. doi:10.1159/000152038

    2008 doi

  16. [2005]

    138(1): p. 13-19. 17

Pith tools

Reviewed August 10, 2026 · model on record in the stance chip above.