Meta-analysis of genetic diversity and intercolony relatedness among reproductives in commercial honey bee populations.

Honey bee colonies are large kin groups, each with a single mother queen and thousands of female workers. Queen bees are highly polyandrous, each mating with an average of approximately 12 drones from other colonies. We used a meta-analysis approach to compare the pedigree relationships of honey bee reproductives (queens and their mates) across five different studies and to quantify the overall genetic diversity of breeding populations. We compared the inferred genotypes of queens and their mates from microsatellite analyses of worker offspring from a feral Africanized honey bee population (which served as a negative control for inbreeding), an experimentally derived population of sister queens (which served as a positive control for inbreeding), and three separate commercially managed populations. We then compared the relatedness of all drones mated to each queen (mate-mate), all queens within each population (queen-queen), each queen with each of her mates (queen-mate), and all drones within each population (drone-drone). We found, as expected, the lowest levels of genetic similarity in the outcrossed population and highest levels of genetic similarity in the inbred population. Levels of genetic similarity among the managed honey bee populations were intermediate but closer to that of the inbred population. Genetic structuring of the entire breeding population resulted in two major subpopulations, likely deriving from breeders on the east and west coast. The effects that these findings have on the overall population genetic diversity of managed honey bees is discussed.

Assessing the mating 'health' of commercial honey bee queens.

Honey bee queens mate with multiple males, which increases the total genetic diversity within colonies and has been shown to confer numerous benefits for colony health and productivity. Recent surveys of beekeepers have suggested that 'poor queens' are a top management concern, thus investigating the reproductive quality and mating success of commercially produced honey bee queens is warranted. We purchased 80 commercially produced queens from large queen breeders in California and measured them for their physical size (fresh weigh and thorax width), insemination success (stored sperm counts and sperm viability), and mating number (determined by patriline genotyping of worker offspring). We found that queens had an average of 4.37 +/- 1.446 million stored sperm in their spermathecae with an average viability of 83.7 +/- 13.33%. We also found that the tested queens had mated with a high number of drones (average effective paternity frequency: 17.0 +/- 8.98). Queen "quality" significantly varied among commercial sources for physical characters but not for mating characters. These findings suggest that it may be more effective to improve overall queen reproductive potential by culling lower-quality queens rather than systematically altering current queen production practices.

Relative turnover numbers of maize endosperm and potato tuber ADP-glucose pyrophosphorylases in the absence and presence of 3-phosphoglyceric acid.

Adenosine diphosphate glucose pyrophosphorylase (AGPase; EC 2.7.7.27) synthesizes the starch precursor, ADP-glucose. It is a rate-limiting enzyme in starch biosynthesis and its activation by 3-phosphoglyceric acid (3PGA) and/or inhibition by inorganic phosphate (Pi) are believed to be physiologically important. Leaf, tuber and cereal embryo AGPases are highly sensitive to these effectors, whereas endosperm AGPases are much less responsive. Two hypotheses can explain the 3PGA activation differences. Compared to leaf AGPases, endosperm AGPases (i) lack the marked ability to be activated by 3PGA or (ii) they are less dependent on 3PGA for activity. The absence of purified preparations has heretofore negated answering this question. To resolve this issue, heterotetrameric maize ( Zea mays L.) endosperm and potato ( Solanum tuberosum L.) tuber AGPases expressed in Escherichia coli were isolated and the relative amounts of enzyme protein were measured by reaction to antibodies against a motif resident in both small subunits. Resulting reaction rates of both AGPases are comparable in the presence but not in the absence of 3PGA when expressed on an active-protein basis. We also placed the potato tuber UpReg1 mutation into the maize AGPase. This mutation greatly enhances 3PGA sensitivity of the potato AGPase but it has little effect on the maize AGPase. Thirdly, lysines known to bind 3PGA in potato tuber AGPase, but missing from the maize endosperm AGPase, were introduced into the maize enzyme. These had minimal effect on maize endosperm activity. In conclusion, the maize endosperm AGPase is not nearly as dependent on 3PGA for activity as is the potato tuber AGPase.