{
  "export": {
    "source": "https://urth.darkrealm.vip/thread/urth/3050",
    "note": "Exported from an unofficial mirror of a public mailing list. Copyright in each message remains with the person who wrote it.  Email addresses are obscured as `user at host`, the form the original archive published. This file was rebuilt from parsed fields rather than retained headers, so it is faithful in content but not byte-exact.",
    "addresses": "obscured as 'user at host'"
  },
  "archive": "urth",
  "thread": {
    "id": 3050,
    "subject": "here is a line on animal polyploidy",
    "messages": 1,
    "voices": 1,
    "first": "2002-03-19T03:10:40+00:00",
    "last": "2002-03-19T03:10:40+00:00"
  },
  "messages": [
    {
      "message_id": "<urth-v0203-376@digest.urth.net>",
      "from": {
        "name": "maa32",
        "address": "maa32 at dana.ucc.nau.edu"
      },
      "date": "2002-03-19T03:10:40+00:00",
      "subject": "(urth) here is a line on animal polyploidy",
      "in_reply_to": null,
      "reply_link": null,
      "blocks": [
        {
          "kind": "text",
          "depth": 0,
          "text": "This is quoted from Dr. R. Neil Jones.  The link is at the bottom if you want \nto read the whole section yourself.\n\n\"3. Polyploidy in animals is known in flatworms, earthworms leeches, \nand brine shrimps, where reproduction is by parthenogenesis or \nhermaphrodites (as you  appreciate plants are better at asexual methods of \nreproduction, and herein lies much of the answer).\nPolyploid amphibians and reptiles are common (salamanders\nand lizards are also parthenogentic).  \nSome bony fish are polyploid, e.g Salmonidae, where sterility of triploids\nis commercially exploited - they dont spawn.  Triploid oysters have\nbeen developed commercially, and this circumvents the unpalatibility\nassociated with spawning (irrelevant but interesting).\nHuman polyploid zygotes arise and mostly die in utero.\nOccasional triploid babies are born, but none survive - this would be\nexplained by lack of genetic balance, which means not explianed.\n\nThe storyline comes down to sex.\nProblems in aninimals with sex determination mechanisms preventing\npolyploids arising, problems with specialised meiotic pairing of \nsex chromosomes (homologous only in part), and then the main thing\nabout polyploidy is that it mucks up meiosis and one needs to \nreproduce by asexual or vegetative means to bypass this.\nAllopolyploidy is OK: i.e species hybrids giving sterile F1, then \nchromosome doubling to give pairing partners within each genomic\nset.  Difficult to see such hybrids arising between cows and sheep.\nI suppose there are some developmental complexities in animals\nwhich also cause a problem.\n\nI dont know about yeast.\n\nI do not think there is any physiological block to polyploidy\nin animals.\"\n\nhttp://iubio.bio.indiana.edu/R22262-25664-/news/bionet/metabolic-reg/9804.newsm\n\nHope this clarifies.  Note that polyploidy most often occurs with hybrids.  \nAnd that is what we are talking about here.\n\nMarc"
        }
      ]
    }
  ]
}