Diploid Drones In Breeding

Discussion in 'Raising Queens' started by ApisBees, Aug 15, 2012.

  1. ApisBees

    ApisBees Active Member

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    I read this in wikipedia. It explains what happens when a queen mates with one of her brothers. It emphasized the need for more hives of genetic diversity when mating queens. The result is you can end up with spotty brood since after the egg hatches in 4 days the young brood is detected and removed leaving holes in the brood that the queen has to relay in. I Know it is rewarding to raise your own queens but if you don't have enough bee hives in your area to provide non related drones your queens are going to be inferior because of the amount of brood being removed because of diploid drone eggs.

    "Drones are produced from unfertilized eggs and therefore represent only the DNA of the queen that laid the eggs, i.e. have only a mother. Workers and queens result from fertilized eggs and therefore have both a mother and a father. A modified form of parthenogenesis controls sex differentiation. The sex allele is polymorphic and so long as two different variants are present, a female bee results. If both sex alleles are identical, diploid drones are produced. Honeybees detect and destroy diploid drones after the eggs hatch.

    Queens typically mate with multiple drones on more than one mating flight. Once mated, they lay eggs and fertilize them as needed from sperm stored in the spermatheca. Since the number of sex alleles is limited - about 18 are known in Apis - there is a high probability that a queen will mate with one or more drones having sex alleles identical with one of the sex alleles in the queen. It is therefore typical for a queen to produce a percentage of diploid drone eggs."
     
  2. PerryBee

    PerryBee New Member

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    Interesting. I did not know that they removed those larvae (might explain a shoddy brood pattern though). Good read.
     

  3. tecumseh

    tecumseh New Member

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    the upside is a quick visual scan of the laying pattern of a given queen should tell you when inbreeding is becoming a problem. you must however also note which cells a queen will never lay in anyway and exclude these from the casual visual survey (as in cells that are directly above inbedded wires).

    the simple strategy is to add genetic material (via buying purchased queens) that is as far removed genetically from your own stock as possible <as a side bar this decision should also add some characteristic that is missing in your current stock.
     
  4. Barbarian

    Barbarian New Member

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    Interesting.

    I wonder how this information squares with breeders who produce "pure" races of bees. How do breeders who have isolated mating stations or flood the local keepers with "free" queens cope with inbreeding ?

    For my small needs I stick to "Breed from the best ---- scrap the rest".
     
  5. tecumseh

    tecumseh New Member

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    essentially Barbarian what we are speaking about here is inbreeding or perhaps more exactly a degree of inbreeding. prior to the time when II was doable inbreeding was a highly valued process used by queen breeders to increase the concentration of a desirable genetic trait. of course at some point the viability of individual would be so compromised that only extreme measures would keep them alive. at this point outbreeding would be initiated to make the individual units more viable.
     
  6. d.magnitude

    d.magnitude New Member

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    I've just been reading a "new to me" book by Steve Taber- Breeding Super Bees

    He goes into a great deal of the value and dangers of inbreeding. Really, when open-mating I think the lesson is to just recognize when you have a problem (via brood viability), and fix it. It's only when you get into instrumental insemenation that you can use inbreeding to your advantage to "fix" traits, other than that you just don't have enough control.

    It's really a great little book. He really emphasizes nutrition in raising great bees & queens, then goes into a great deal of genetics (mostly over my head and not necessarily relevant to open mating), and finishes with some nitty-gritty of the queen biz.

    -Dan
     
  7. Lburou

    Lburou Member

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    Another gap in my education

    I'm glad you posted Apis. I was reading one of Brother Adam's books containing a detailed explanation of this subject. I was soon deeper than my interest would take me. While I was reading your OP however, my recent reading in Randy Oliver's pages came back to me. Specifically, how the brood pattern can be scattered in association with viruses and the sickness in the brood they enable via lowered immune responses.

    I discovered another gap in my education as it dawned on me that there are a number of causes for irregularities in a brood pattern. Brood pattern irregularities can be a queen problem, or even a sickness in the brood as mentioned in this article by Randy Oliver.

    When you look at an abnormally scattered frame of brood to see brood of all ages interspersed with older brood, something is compelling the bees to clean those cells out and let the queen have another try at it. The queen could be skipping cells because of a physical or genetic defect, immaturity, or, the bees could be cleaning those cells because of sickness or genetic anomaly.....Perhaps even some other reason.

    I used to think scattered brood patterns were from a weak queen....While I realize that can be true, I now realize that there are a number of other causes. Scattered brood doesn't mean much by itself, I need to get more familiar with ALL the causes and how to recognize patterns within the hive that give us clues to solve for an accurate status of the hive.

    Does anyone know some subtle brood symptoms that cluster around viral, fungal, or bacterial sickness in the brood that would differentiate brood sicknesses from the brood appearance resulting from removal of the diploid larva? :)
     
  8. d.magnitude

    d.magnitude New Member

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    I'd like to know the answer to that last question myself.

    Just to further complicate that line of thought you were on, Lburou, a bad brood pattern could indicate: a bad queen or disease (as you said), or it could indicate that you have highly hygenic stock.
     
  9. Crofter

    Crofter New Member

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    I had one troubled hive that had symptoms that could certainly meet a lot of the mentioned possibilities. Very spotty and very interspersed brood pattern, lots of empty cells; earlier there had been some multiple eggs. The queen supposedly from quite hygenic stock. The mite count was high and after a course of multiple Hopguard and a feeding of Fumidil, things started to straighten out. We did not identify any Nosema on a sample slide but are grass green in this.

    An interspersed pattern is very hard to make regular without a brood break but the new drawn frames went regular and that hive boomed. I can only presume now that mites was the problem but at the outset one could see many possibilities. I have fed about 60 pounds of gain into the hive and hope it makes the winter so I can see how that queen really was genetically.
     
  10. Lburou

    Lburou Member

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    Excellent point! The question popping into my mind when considering that point is why are they being hygenic? Is it because of mites? Or, could it be sacbrood, chilled brood, or some other brood disease?

    I saw bald brood for the first time this summer. I've read where that hygenic traits can go too far and take brood out unnecessarily. :)
     
  11. Daniel Y

    Daniel Y New Member

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    Teh isue of how much genetic diversity is enough is an important one. One bit of information I can offer is in the breeding of Seramas or miniature chickens. originally 153 unrelated pairs where imported to the US. this was considered an extremely meager genetic diversity. No additonl diversity has been imported. There are programs under way to breed the Serama to other small chickens in order to increase the genetic diversity though. It is fairly well recognized that a 10 times number of original pairs would barely be breaking minimal desired genetic pools though.

    This has always shed some light on what a good genetic pool needs to look like.
     
  12. Zookeep

    Zookeep Active Member

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    thats real good to know about the drones and gene pool, makes me happy cause my hives come from 200 miles south of me to 150 miles north, genes spread out all over the place, and I plan on using just 2 hives for queens and I will make sure those 2 hives produce little or no drones.
     
  13. ApisBees

    ApisBees Active Member

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    Good plan Zookeep or place your mating nucs in a yard a few miles away from your queen breeder colonies.
     
  14. Ray

    Ray Member

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    The amount of diploid drones would indicate the amount of inbreeding. Correct?

    To increase genetic diversity should a beek bring in less popular strains of honeybees?
     
  15. Daniel Y

    Daniel Y New Member

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    I have taken up the task of considering, only considering mind you. of getting into queen Breeding. With an emphasis on working toward that all around kept bee.

    So far my plan calls for a whole lot of work over the next 4 and a half years.

    Part of the plan includes taking a very close look and searching out the latest information in regard to breeding. genetics breeding issues etc.

    In breeding in general gene pool reduction or narrowing is both a goal and a concern.

    It is a goal in that breeding itself is the selection of any animal in an attempt to rid it of undesirable traits. Undesirable traits are the result of undesirable genes.

    It is a concern in that reduced genetic diversity can and will cause many issue such as this thread explains.

    What I have found about the Honey Bee and it's sex genes. Unlike most other animals that only have two possible sex genes, an X or a Y. Honey bees have as many as 19 possible sex genes.
    These are listed alphabetically A thru S.

    Any given queen will posses only two out of these 19. obviously already a drastic reduction of that gene selection. Obvious solution. keep more than one queen.

    The queen pass only one of her two genes to any egg she lays. Again further reduction of the possible genes. now all the way from 19 to 1. This is not necessarily a bad thing or necessarily unwanted. it just needs to be understood so that it can be used in whatever manner is chosen. You may want to avid it. you may not.

    Another unique thing about the honey bee is how sex is determined. it is not determined as in most animals by a certain combination of sex genes. but simply by weather a bee contains two different genes or one or two of the same gene. Different genes means female. one or two of the same means a male. Two genes even though they are the same results in a diploid male and is a fatal gene combination. This means diploid drones although possible do not survive. in fact they are killed by the worker bees shortly after the egg hatches.

    So one way to possibly determine that spotty brood is the result of diploid eggs is that you have a high rate of spotty brood soon after eggs have hatched at day 4. any spotty brood issue that are the result of capped cells being opened etc. are going to be from some other cause.

    In addition another unique situation of honey bees is that drones only carry one set of genes. Think of a drone as just a sperm cell with wings. It also has the ability to make millions of addition sperm that are clones of itself.


    One way the bee counters this drastic reduction of possible sex genes is that the queen will mate with multiple drones. 10 to 12 are normal but queens may mate with as many as 20 or more. As you can see it is possible that between the two genes she already possesses and a total of 20 different mating. a queen could in fact hold all 19 sex genes in either her eggs or in the sperm she stores. Instant cure to gene pool reduction.

    It is pretty easy to see that the key to keeping a wide genetic diversity is through drones not queens.

    So how does all this apply to the sister mating with brother

    A queen that has sex genes A and B will lay an egg that is fertilized with the sperm of a drone with sex gene C. This new female now carries Sex Genes A and C. It is reared to be a queen.

    At this same time the Queen is laying a certain number of eggs that are unfertilized and will produce equal numbers of drones with either sex gene A or sex Gene B.

    Since in my perfect world the only drones this AC virgin queen has to mate with are her brothers. It does not matter how many matings she has. She will end up with sperm in equal number that have either A or B sex genes. You can at this point simplify the drones genes by simply saying she mated with one drone that carried both the A and B gene.

    At this point you have a AC Queen and an AB drone. This means that any random pairing of an egg and a sperm could result in. AA(fatal), AB, CA, or CB. Only one out of 4 even in brother to sister inbreeding results in a diploid male (AA). This will result in a 25% brood loss to diploid males alone. I don't think such a heavily spotted brood patter is going to go unnoticed even with casual inspections.

    If we take this one generation further. Or try to continue breeding with inbreeding methods. we have a queen that can only produce AB, CA or CB daughters. again these can only mate with either A or C Brothers.

    A AB sister mating with an A brother can then produce AA or BA offspring 50% fatal.
    A AB sister mating with an C Brother can produce AC or BC offspring 0% fatal.
    A CA sister mating with a A brother can produce CA or AA offspring 50% fatal.
    A CB sister mating with a C brother can produce CC or BC offspring 50% fatal.

    A full 75% of all possible matings will result in 50% diploid drones. This is actually huge and could very well be a guarantee no such colony could survive. it will be self cleansing from the gene pool. It will certainly not inspection and will be requeened.

    I can carry this on for another generation but it is not necessary it is it simply understood that all we have are 3 genes to play with and every generation is simply going to make it more likely that fatal matches are made.

    So how is inbreeding a good thing? Well we are looking at how it works considering sex genes and a result we would not want. but it also has the same sort of effect on things we do want as well. So lets say we apply the same idea to genes for hygienic behavior. in the same way we can increase the likelihood that we will get the desirable combination.

    In breeding is a method not necessarily an evil. like any other method it has it's dangers. but that does not mean we want to necessarily completely avoid it. It has it's uses as well. But it is best if knowledge accompanies it's use.
     
  16. Daniel Y

    Daniel Y New Member

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    I did mention this in my lengthy post above but wanted to repeat it because lengthy posts are at risk of not being read.

    Diplod Drones are destroyed shortly after the egg hatches. so one particular symptom of diploid drones being the problems rather than disease is that spotty brood is observed at very early stages of larva development. This woudl not be the only cause of spotty brood at early development stages but it could help you determine that spotty brood is not the result of diploid drones. Good pattern in uncapped but older larva means no diplod problem.
     
  17. ApisBees

    ApisBees Active Member

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    Good follow up thread Daniel Y. It make one think about the problems with queen rearing and an appreciation for ones who have spent the time developing their queen stock programs.
     
  18. Daniel Y

    Daniel Y New Member

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    Okay just for the sake of information and follow up. I have spent some time since my last post looking into this drone issue. and here it is. Not complete but what I have found so far.

    We have to look at what happens in the genes of a bee and how they are different. specifically the genes that determine sex.

    In nearly all other animals there are only 2 genes that determine sex. an X and Y. And every animal has two. A female has two of the same gene while a male has one of each. Sex is determined by different or same.
    Different and same will also determine sex in a bee just like other animals. But. bees do not have just 2 genes that determine sex. they have 19. In addition an more importunity two sex genes in a male bee is fatal. drones with two sex genes die soon after the egg hatches. So in reality surviving sex in bees is due to number of sex genes not difference and same as in other animals. In bees 1 gene means a male that survives. and two genes is female. males with 2 genes do not survive.

    In bees the 19 sex genes are all considered X genes. and are symbolized as Xa, Xb, Xc, etc all the way to Xs.

    So lets see what happens when the beekeeper mates the best to his best like the farmers did and track just the sex gene. remembered that any two genes of the same are fatal. This is critical.

    The virgin queen has two sex gens and we know they must be different. So we will say she has genes Xa and Xb. We know queens mate with multiple drones, but to keep this simple I will say she only mates with two. We know that each drone has only one sex gene because they are still alive to mate. So we will assume that they also have different sex genes. and call them Xc and Xd.

    Now you can try to map this out as far as an entire apiary is concerned or you can take my word for it. the math works regardless of the number of bees that are mating. It will have the same result. This is a micro look at what happens in inbreeding with bees.

    Now the only offspring that can possibly be produced are Xac or Xad Xbc or X bd females and only drone with an Xa or Xb gene. Take careful notice at this point at what has happened to that pool of 19 genes already after just one mating. it has been reduced to a pool of 4. The chance of same sex gene pairing has been drastically increased already. but none accour in this first generation. all looks perfectly fine. in fact the beekeeper probably sees an improvement. so he keeps all is colonies and they randomly mate among each other.

    We will follow just one random queen of the second generation. I actually rolled a dice to pick her and it came up queen Xbc. So there is not trick in this being the result. She only has drones Xa and Xb that she can possibly mate with. remember her sisters have not mated either they cannot yet produce drones.

    She has a 50 50 chance of mating with the Xb drone. This woudl men she will produce in equal number offspring with Xbb (fatal) Xcd female or Xb and Xc drones. Half of all fertile eggs will not survive.

    Now that is a condensed get right to the point tracking of worst case leading to worst case.

    But it shows shy breeding bees like they have bred every other agricultural animals does not produce the same results. In fact it results in a serious decline in survivability in just a few generations. Breeding the best with the best is still the answer. but with a but of an alteration that prevents that sex gene from becoming so limited.