"Haldane's rule" meaning in English

{
  "etymology_text": "Formulated in 1922 by the British evolutionary biologist J. B. S. Haldane.",
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  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
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      "examples": [
        {
          "ref": "2018, Tim Flannery, Europe: The First 100 Million Years, Penguin, published 2019, page 181",
          "text": "One study hints at the possibility that Haldane's rule may have been the cause of the lack of Neanderthal DNA on the Y-chromosome of hybrids, but currently we do not definitively know.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An observation about the early stage of speciation, stating that if in a species hybrid only one sex is inviable or sterile, that sex is more likely to be the heterogametic sex."
      ],
      "id": "en-Haldane's_rule-en-name-duyvqWux",
      "links": [
        [
          "speciation",
          "speciation"
        ],
        [
          "species",
          "species"
        ],
        [
          "hybrid",
          "hybrid"
        ],
        [
          "sex",
          "sex"
        ],
        [
          "inviable",
          "inviable"
        ],
        [
          "sterile",
          "sterile"
        ],
        [
          "heterogametic",
          "heterogametic"
        ]
      ],
      "wikipedia": [
        "Haldane's rule"
      ]
    }
  ],
  "word": "Haldane's rule"
}

{
  "etymology_text": "Formulated in 1922 by the British evolutionary biologist J. B. S. Haldane.",
  "head_templates": [
    {
      "args": {},
      "expansion": "Haldane's rule",
      "name": "en-proper noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "name",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English entries with language name categories using raw markup",
        "English eponyms",
        "English lemmas",
        "English multiword terms",
        "English proper nouns",
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        "English terms with quotations",
        "English uncountable nouns",
        "Quotation templates to be cleaned"
      ],
      "examples": [
        {
          "ref": "2018, Tim Flannery, Europe: The First 100 Million Years, Penguin, published 2019, page 181",
          "text": "One study hints at the possibility that Haldane's rule may have been the cause of the lack of Neanderthal DNA on the Y-chromosome of hybrids, but currently we do not definitively know.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "An observation about the early stage of speciation, stating that if in a species hybrid only one sex is inviable or sterile, that sex is more likely to be the heterogametic sex."
      ],
      "links": [
        [
          "speciation",
          "speciation"
        ],
        [
          "species",
          "species"
        ],
        [
          "hybrid",
          "hybrid"
        ],
        [
          "sex",
          "sex"
        ],
        [
          "inviable",
          "inviable"
        ],
        [
          "sterile",
          "sterile"
        ],
        [
          "heterogametic",
          "heterogametic"
        ]
      ],
      "wikipedia": [
        "Haldane's rule"
      ]
    }
  ],
  "word": "Haldane's rule"
}