Promiscuous Queens.

[Norton]

which would have been easy enough to do as all drones from one queen are genetically the same.

Incorrect!

 

[alanf]

Genetic 'remix' Key to Evolution of Bee Behavior.,,,

OK, so honey bee DNA is recombined more frequently than other animals. That would tend to suggest that a single advantageous mutation spreads more rapidly than it would otherwise because it is more likely to be decoupled from the rest of the genome. To spread rapidly, the new mutation displaces established disadvantaged versions of the gene in a wider range of existing genomes than would otherwise be the case.

Yet the links that started this thread argued that it was genetic diversity that benefits the colony as a whole. I recall a similar finding described in a Keith Delaplane lecture which probably indicates diversity is getting some attention in the US. I'm not sure that increasing the rate of remixing would be linked to benefits from the genetic diversity of a colony.

Take the "dragon boat" analogy that the researchers have used. Boats are mixing crews more rapidly, winning boats get to breed and pass on that characteristic. Whatever "good rowers" turn out to be in specific circumstances come to dominate the population of rowers more rapidly than in other species. However, the earlier linked papers suggested that a diversity of rowers had an advantage; closer to a mix of sprint rowers, stamina rowers, varied course strategies and so on. Maybe stretching the analogy past it's usefulness but the point is that rapid recombinations would tend to increase selection for specific mutations; advantages for diversity would work in the opposite direction.

Maybe the link is that the rapid recombination can be tolerated because the higher genetic pressure of selection is countered by the advantage for diversity that keeps varied alleles in circulation. Just a thought exercise.

 

[drstitson]

"OK, so honey bee DNA is recombined more frequently than other animals. That would tend to suggest that a single advantageous mutation spreads more rapidly than it would otherwise because it is more likely to be decoupled from the rest of the genome. To spread rapidly, the new mutation displaces established disadvantaged versions of the gene in a wider range of existing genomes than would otherwise be the case. "

NO. recombination just means that any particular allele of any single gene may not find itself on the same chromosome in a gamete (sperm or egg; or just egg in honeybees) wrt parent genome.

so all recombination does is mean that even if you inherit an apparently identical set of parental chromosomes there will be some differences between two individuals. the only exception would be if it were possible for a parthenogenetically produced diploid organism (so 2 identical copies of a full haploid genome) to subsequently reproduce. the only differences between the inherited half genome of next generation and parent would be rare sporadic accumulated germ line mutations.

The recombination in bees just means that even in a relatively stable breeding strain there is enough mixing-up of what is otherwise fixed to provide greater variation in offspring. remember even in pure bred strains sexual reproduction results in similar but uniquely different individuals rather than clones.

That's the real joy of sex. And believe me it lasts longer that the brief messy fun stuff (by which i mean the physical act of recombination, of course!).

DOI: Ex-postgrad in Mammalian Sex Determination Group in Cambridge Genetics Dept.

 

[pargyle]

Is there any evidence that colonies themselves practice selection ? ... I've read enough about queen supercedure to understand that, if the 'committee' is not happy with the queen they have, they just get on and raise a new one. If they sense that some quality in the queen is not fit for purpose then it's not a massive leap to suggest that they may not tolerate inferior workers or drones ? Those dead bees we see in front of the hive or on the floor may not all be death by natural causes ?

 

[drstitson]

"That would tend to suggest that a single advantageous mutation spreads more rapidly than it would otherwise because it is more likely to be decoupled from the rest of the genome"

there is no specific decoupling of specific genes; an advantageous mutation would not get preferentially recombined. it's just a random mash up. and it of course all happens before the individual can take advantage of the mutation!

but the mixed backgrounds do give more change of finding a winning combination than in a stagnant situation.

the dragon boat analogy is a good one - but you need some selection NOT just winning. perhaps moving to next round and so on.

 

[alanf]

recombination just means that any particular allele of any single gene may not find itself on the same chromosome in a gamete (sperm or egg; or just egg in honeybees) wrt parent genome...

I don't think anything I wrote suggests otherwise. It follows from the researcher's remarks:

"The honey bee has the highest rates of recombination in animals – ten times higher than humans. Our study shows that this high degree of genetic shuffling has turned on the evolutionary faucet in parts of the bee genome responsible for orchestrating worker behaviour," says Kent. "This can allow natural selection to increase the fitness of honey bee colonies, which live or die based on how well their workers 'behave'.

If recombination is at a higher rate than elsewhere, then a novel mutation would be tried in a greater variety of parent genomes than it would in other animals. If it confers advantage, that variation will be reproduced more than other variations. Genetics textbook stuff.

My point is that would be at odds with the earlier papers in the thread that suggested diversity of parentage had an advantage. That is, diversity keeps many alleles going in a population, when honey bees seem to have a recombination rate that would tend to reduce diversity.

the mixed backgrounds do give more change (chance?) of finding a winning combination than in a stagnant situation.

Just so, the idea that there could be a reproducible "winning combination" in honey bees is contradicted by the advantage of diversity according to Mattila, Cobey, Delaplane and others.

 

[drstitson]

alan - i was questioning your initial statement that seemed to imply that a higher recombination rate means that advantageous genes are more likely to be decoupled.

not wrt other genes in same genome; just wrt another genome with lower recombination rate.

Sure recombination provides the means for genes to be tested in a wider range of backgrounds and potentially increase their ability to succeed.

BUT the underlying rate of that recombination will not change according to how good the gene is UNLESS there is, by chance, a linked recombination hotspot.

However, any increased local recombination could also have a negative effect, splitting the beneficial gene from better backgrounds.

 

[alanf]

alan - i was questioning your initial statement that seemed to imply that a higher recombination rate means that advantageous genes are more likely to be decoupled.

Not an intended implication. A high recombination rate gets a specific allele appearing alongside others more quickly than it would in other organisms. Applies whether that allele has an advantage or disadvantage alike. A change in advantage would then produce a shift in the proportions of specific allele types in a population. And that shift could be expected to appear in fewer generations than it might in another species. As you said, the "winning combination" appears a little sooner than if the recombination was less rapid.

Interesting questions that leads to are: if that high recombination rate is a benefit, why don't we see the same high recombination rate appearing in other organisms? How widespread is that rapid evolution of behaviour? If it's an advantage for social insects do ants and wasps have the same trait? Or is it shared with solitary bees? And, from the earlier quoted papers, how does it work in combination with any advantage from diversity? As usual, an answer adds more questions.

 

[Hivemaker.]

This newer research belongs in this thread as well.

Interesting results using instrumental insemination.

Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites
Published: December 21, 2015
DOI: 10.1371/journal.pone.0142985

Abstract

A honey bee queen mates on wing with an average of 12 males and stores their sperm to produce progeny of mixed paternity. The degree of a queen’s polyandry is positively associated with measures of her colony’s fitness, and observed distributions of mating number are evolutionary optima balancing risks of mating flights against benefits to the colony. Effective mating numbers as high as 40 have been documented, begging the question of the upper bounds of this behavior that can be expected to confer colony benefit. In this study we used instrumental insemination to create three classes of queens with exaggerated range of polyandry– 15, 30, or 60 drones. Colonies headed by queens inseminated with 30 or 60 drones produced more brood per bee and had a lower proportion of samples positive for Varroa destructor mites than colonies whose queens were inseminated with 15 drones, suggesting benefits of polyandry at rates higher than those normally obtaining in nature. Our results are consistent with two hypotheses that posit conditions that reward such high expressions of polyandry: (1) a queen may mate with many males in order to promote beneficial non-additive genetic interactions among subfamilies, and (2) a queen may mate with many males in order to capture a large number of rare alleles that regulate resistance to pathogens and parasites in a breeding population. Our results are unique for identifying the highest levels of polyandry yet detected that confer colony-level benefit and for showing a benefit of polyandry in particular toward the parasitic mite V. destructor.

Full paper below.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142985

 

[user 6228]

This newer research belongs in this thread as well.

Interesting results using instrumental insemination.

Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites
Published: December 21, 2015
DOI: 10.1371/journal.pone.0142985






Full paper below.
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0142985

The honeybee may have benefited from the frequent glaciations in Europe, compressing divergent genetic strains together so stirring the genetic pot

 

[Finman]

.
You out there know much about genes, but you do not want you breed off European foul brood from British bee genepool. It would be easy to do that.

 

[B+.]

Honey Bee Colonies Headed by Hyperpolyandrous Queens Have Improved Brood Rearing Efficiency and Lower Infestation Rates of Parasitic Varroa Mites

V. interesting HM. The Dutch BeeBreed group have been pursuing the single drone insemination route to VSH so this is an interesting counter