[Subjectivist]

Turkeys are one of the few domesticated species in which parthenogenesis has been proven and extensively studied. If you put 100 turkey hens in an enclosed pasture and protect them from predators then when they are mature they will lay an average of 8 eggs per month. Once they have a clutch of eggs they will incubate them for four weeks even if they had no Toms in the flock to fertilize them. After four weeks of the 800 eggs being incubated two will hatch, despite none of them ever being fertilized. Both of the hatchlings will be males, reverse gender clones of the hens which laid them.

After the two hatchlings reach sexual maturity in a few months they will mate as often as possible and many of the eggs laid in the next season will be fertilized and develop normally leading to a roughly equal number of chicks of each gender.

This effect was first noted in the 1950's and has been studied extensively ever since then. When I was a child there was hope that an artificial trigger could be discovered so that farmers would not need to manually fertilize the hens to breed meat birds for Thanks Giving dinner. All of the viable chicks have always been males so even if they do figure out a trigger someday the poults will not be able to continue the next generation asexually, they will need hens to breed with.

Parthenogenesis is a fascinating survival trait demonstrated by many invertebrates, many fish, lizards and a few birds. Sharks in zoos where all of he specimens have demonstrated parthenogenesis at least twice, both in the Hammerhead and Black Fin species. In the case of the sharks the resulting offspring are clones of the mother. So far it has never been demonstrated in mammels, but there has not been an extensive gene mapping project to prove that all the female offspring are not clones of their mothers.

I would be especially interested in any studies of the few surviving species of mammels that lay eggs, they seem like the most likely candidates.

[Shaved Monkey]

i think its pretty common in fish
All barramundi begin their lives as male, changing sex to female at a weight of around 5kg.

[Subjectivist]

While the fish changing gender is an interesting trait what the sharks did in captivity was parthenogenesis, not gender shifting.

What the hammerhead shark did was to produce an egg that had two identcal sets of chromosomes, a diploid set made by doubling the normal haploid compliment of an unfertilized egg cell. Normally a male would contribute a haploid set making the full diploid set needed for normal sexual reproduction. They know this for certain because the zoo in question had three juvinile females captured and confined without a male present for years before one of them gave birth. Genetic testing was done proving that the baby female shark shared 50 % of its genes with one of the now adult females but had two identical copies of all of its own chromosomes. The only way for hat to happen is for the egg to go through regular meiosis shedding half of its chromosomes, then copy the remainin set in the nucleus somehow to get a full set of doubled chromosome pairs.

When a turkey egg does this most of the time the egg that manages to double its haploid set dies because only the double set that leads to a male is viable. In Turkeys the female gene is the mixed pair, the opposite of how it works for humans. If Tukeys ever produce viable parthenogenetic female offspring it has not been observed in almost 70 years of experimenting on them. In Turkeys the odds of a viable parthenogenetic unfertilized egg is 3/1000. Not all of the male hatchlings thrive, but some of them do which provides enough healthy males for sexual reproduction in the next generation.

The third generation males have normal diploid chromosome sets and from then on the breeding results are indistiguishable from any other random breeding by normal male Tom Turkeys. It is known that even when turkeys breed there is no garuntee that all of he eggs in the clutch will be fertilized. This raises the possibility that a small number of male turkeys in each generation are actually partheogenetic in origin.

[Subjectivist]

Bump for Turkey Day.

[Newfie]

Thanks, I teresting.

[careinke]

My turkeys were acting nervous today.



I'll probably take them next week. They have completed the winter cleaning of the garden, now I need to let my kale recover. Surprisingly they have no interest in carrot or parsnip plants. Lucky me.

[Tanada]

My turkeys were acting nervous today.

I'll probably take them next week. They have completed the winter cleaning of the garden, now I need to let my kale recover. Surprisingly they have no interest in carrot or parsnip plants. Lucky me.

Handsome birds with lots of healthy dark meat

I feel sorry for those poor inbred butterball turkeys with their oversize breasts and inability to breed naturally. A butterball male has so much breast meat on his skeleton he can't make the necessary connection to breed with a butterball or conventional female. In my book livestock or poultry that can not reproduce naturally are kind of creepy.

[vtsnowedin]

I feel sorry for those poor inbred butterball turkeys with their oversize breasts and inability to breed naturally. A butterball male has so much breast meat on his skeleton he can't make the necessary connection to breed with a butterball or conventional female. In my book livestock or poultry that can not reproduce naturally are kind of creepy.

Why does that bring the Kardashians to mind.

[Rod_Cloutier]

Thanksgiving is in mid-October in Canada- it is long past.

I have always wondered why the US has its Thanksgiving a month late.

[Subjectivist]

Thanksgiving is in mid-October in Canada- it is long past.

I have always wondered why the US has its Thanksgiving a month late.

Thanksgiving is a celebration of the harvest and across most of America harvest is just finishing or still going strong this time of year.