Thursday, November 22, 2007

This Week's Citation Classic

Olsen MW & Mardsen SJ. 1954. Natural parthenogenesis in turkey eggs. SCIENCE 120 (3118): 545-546.

Almost all vertebrates reproduce sexually, i.e. the sperm and egg join to form an embryo. Vertebrates that reproduce asexually are exceptionally rare, however turkeys are one such species that can do so. Many explanations are given as to why turkeys reproduce asexually on occasion (as high as 40% of offspring are products of parthenogenesis): low sperm count, male unavailability etc. I'll offer one of my own. Female turkeys see males (photo above) and think, "No way in hell am I having sex with that!"

Here is a quote from the Ohio State University 4H site:

Dr. M. W. Olsen working for the United States Department of Agriculture extensively studied the development of parthenogenesis in turkeys. He worked with a small variety of turkeys called Beltsville Small Whites. He found that the onset of parthenogenetic development in turkeys takes place three or four hours prior to ovulation or soon after ovulation of the ovarian follicle from the ovary. In Dr. Olsen’s early studies, the parthenogenetic development in eggs from nonmated hens would only proceed though the development of membranes and early blood formation by the embryo. He bred a strain of Beltsville Small Whites for a higher incidence of parthenogenesis in unfertilized eggs. As selection continued, the incidence of the condition increased and parthenogenic development proceeded to more advanced stages until an embryo that developed parthenogenetically from an unfertilized egg. The first poult that hatched by this method was moved, for safe keeping, from the research farm to Dr. Olsen’s basement. Unfortunately, his dog killed the turkey.

Whoops!

Happy Thanksgiving!!!

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