Bio 113P Lab 3: Phenotypic Effects of Wolbachia on the Reproductive Behaviors and Outcomes of Nason

Bio 113P Lab 3: Phenotypic Effects of Wolbachia on the Reproductive Behaviors and Outcomes of Nason

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Phenotypic Effects of Wolba c hia on the Reproductive Behaviors and Outcomes of Na s onia Vi t rip e nni Manuel Vazquez 4/02/12
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
INTRODUCTION Wolba c hia is an endosymbiotic bacteria that lives as a reproductive parasite in a large fraction of insect species worldwide. In order to be passed on to future generations, the infection must be present in the eggs of the mother, since it lives in the cytoplasm of the cells of the reproductive system, but most of the cytoplasm is removed from the sperm cells during development ± thus, the infection is only inherited via the mother. This means that it is most favorable for to be present in females, and for the offspring of a pairing of insects to be mostly or all female as well. To this end, the parasitic bacterium has various methods of subterfuge which can be used to hijack the reproductive systems of its host. One such host of is Na s onia Vi t rip e nni , a parasitic wasp that is dependent on certain flies for its lifecycle. onia females, in order to lay their eggs, must find a pupating fly to act as a host: once located, the females will drill a hole through the puparium wall, and inject venom into it to kill the larva inside. They then proceed to lay their eggs on the surface of the fly pupa, which then hatch and consume it for food as they grow, pupate, and metamorphosize inside the pupal casing, and finally emerge. reproduces through a haplo-diplo mating system, where an unfertilized female will lay haploid offspring, which will result in males, and where a fertilized female will lay diploid offspring, rearing more females. , however, interferes with this normal cycle by four main mechanisms of disruption: feminization, male killing, parthenogenesis, and cytoplasmic incompatibility (CI). In CI, the sperm of infected males and uninfected females, or of females infected with a different strain of , are rendered incompatible with one another due to ¶V LQWHUIHUHQFH ZLWK WKH GHYHORSPHQW RI WKH JDPHWHV² UHVXOWLQJ LQ D failure of fertilization, and thus in all-male broods; in contrast, in parthenogenesis, unfertilized females will develop diploid eggs which in turn form all-female broods from unfertilized eggs. Male killing is the result of successful copulation, whereby -infected haploid eggs are killed by the infection itself, leaving only diploid eggs in the brood, and thus resulting in an all- female, but much smaller than normal, filial generation; this presumably serves the purpose of reserving all the available resources for the diploid female offspring, thus increasing their chance of surviving and passing on the infection, by eliminating those known not to pass on the infection. Finally, in feminization, the will override the normal masculine development of the haploid males, and instead force them to become haploid females and pseudo-females, which are often infertile. (Werren, 2003) From the patterns of offspring formation thus described, this experiment was conceived with two main goals in mind: the fir VW JRDO RI WKH H[SHULPHQW ZDV WR DQVZHU WKH TXHVWLRQ ³GRHV
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 6

Bio 113P Lab 3: Phenotypic Effects of Wolbachia on the Reproductive Behaviors and Outcomes of Nason

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online