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http://minnesotabirdnerd.blogspot.com/2009/01/i-just-received-coolest-bird-photo-ive.html

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http://minnesotabirdnerd.blogspot.com/2009/01/i-just-received-coolest-bird-photo-ive.html

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  1. AGYNANDROMORPHisA non-human organism that contains both male and female characteristics.Varieties:Bilateral Symmetrical Gynandromorphy: One side of a creature is completely male; other side is completely female. Organisms with this variety of the syndrome will usually look as though they are split down the middle, like the cardinal below.Mosaic Gynandromorphy: Differentiation between the two sexes is less clear http://minnesotabirdnerd.blogspot.com/2009/01/i-just-received-coolest-bird-photo-ive.html

  2. Gynandromorphy in Birds • Gynandromorphy occurs when sex cells do not separate correctly during the early embryonic phase. • In birds, some cells will have ZW chromosomes (female genoytype), some will have ZZ chromosomes (male genotype). • Plumage in birds is impacted solely by genetics—not hormones

  3. Birds and Hormones • Birds are unique in that cells don’t wait for hormonal cues from sex organs to determine gender—they know whether they’re male or female from the start • Conversely, in human development, somatic cells start off unisex; they don’t develop into male or female cells (though marked by chromosomes) until gonads begins developing hormones at around seven weeks • In some species (chickens, finches), embryos exhibit “maleness” or “femaleness” after eighteen hours, long before the gonads form http://www.pnas.org/content/100/8/4873/F1.large.jpg

  4. Methods of Discovery • Majority of research on this syndrome is completed at the University of California, Los Angeles, where animal use has been approved. • Researchers observe reproductive behavior of both males and females for twenty-one months and then take tissue samples • To test to see if cells are male or female, scientists removed cells from embryos that had not yet formed gonads, and inserted these cells into eggs containing male and female birds, which created partial gynandromorphs • Researchers found that suppressing the DMRT-1 on the Z chromosomein male chick embryos made them develop a testis with feminine characteristics. • http://news.sciencemag.org/sciencenow/2010/03/no-sexual-confusion-for-chicken.html

  5. Sam (Samantha/Samuel) , the gynandromorph Chicken -Gynandromorph chicken, left. The 'cockerel' side of the bird has white feathers, large wattles and breast muscles, whereas the smaller 'hen' side has characteristic dark colouring. -This bird is unable to reproduce, and thinks it is male. Its cells on the two sides are completely different. -A female chicken into which male cells are inserted will not switch sex roles, and visa versa. http://www.bioedonline.org/news/news.cfm?art=6174

  6. Scientists’ Agenda • Next on the docket for scientists studying gynandromorphy is the task of trying to determine by just how much these sex differences precede sex-hormone influences • Researchers predict that bird cells will know at the moment of fertilization whether they’re male or female • Conclusion: birds follow different developmental patterns than other animals • Gynandromorphy is studied primarily in finches, cardinals and chickens, but scientists want to research the syndrome in bird species where the sex differences aren’t as clearly pronounced http://www.bioedonline.org/news/news.cfm?art=6174s

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