4.3 reproductive technologies

1. 4.3 reproductive technologies Ms. De Sousa SBI3U

2. PrenatalTesting • Test performed on a fetusthat looks for geneticabnormalities • In Ontario, the cost of prenataltestingiscovered by OHIP. • Nowadays, women of all agesare recommended to have prenatalgenetictesting. • There are variousethical issues involved in thisprocedure

3. Prenataltestingprocedures • The expectingmother has an ultrasound and bloodwork. • Fetalproteins, image of the fetus and fluidat the back of the fetus’ neck are analyzed • Depending on the results, more invasive tests maybeperformed, such as collecting the fetus’ DNA.

5. Reproductive strategies • Reproductive technologies have been used for manyyears to obtaindesirable traits in livestock and plant crops. • For example, many people select desirable traits to produce good housepets. Withthese new technologies, woulditbe possible to select desirable traits in an offspring?

6. agriculture • Selectivebreeding: process of breeding plants and animals for desirable traits. Many new breeds of animals and plants have been developped due to selectivebreeding. Within agriculture there are threemethodsthat people use in order to select these traits.

7. agriculture 2) ArtificialInsemination: the spermiscollected and concentrated and laterintroducedinto the female’s reproductive system. • The semenfromhigh-quality males isstored. • Pet ownersthenchoose the desirable traits.

8. Agriculture 3) Embryo Transfer: an eggisfertilizedin a culture and transfered to a femalerecipient. This procedureissimilar to In vitro Fertilizationused in humans.

9. Reproductive technologies in humans • There are numerous technologies available for married couples who are not able to conceive. • All of these technologies are refered to as « Assisted Reproductive Technologies » (ART) • The following technologies are used in humans: 1) ArtificialInsemination 2) In virtofertilization

10. a) Artificialinsemination • Similar to artificialinseminationused in agriculture. • The semenisstoredand latertransfered to a female’sreproductive tract. • The donorspermcaneitherbe the woman’spartner or from an unknown source.

11. B) In vitro Fertilization (IVF) • Generallyused for womenwithblockedfallopian tube. • Immature eggsare retrieved and combine withsperm in the laboratory. • Once the eggisfertilized, the zygoteisplacedinto the women’suterus. • Nowadays, over 1.5 million babies are conceivedthrough IVF.

12. Whatis the main differencebetween IVF and ArtificialInsemmination?

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14. Preimplantationgeneticdiagnosis • A genetic test thatallowsdiagnosis of geneticdisorders. • This occursbefore the zygote of IVF istransferedinto the female. • Once the zygote divides, one of the cellsisanalyzed. • Only the healthyembryosare implantedinto the uterus.

15. Reproductive technology: cloning • Processthatreproducesidentical copies of genes, cells or organisms. • There are 3 main types: a) Gene Cloning b) TherapeuticCloning c) Reproductive Cloning

16. 1) Gene Cloning • Manipulation of DNA to producemany copies of a desiredDNA sequence. • The copied DNA istransfered to a foreignorganism. • This procedure has made insulinmore readilyavailable for patients withdiabetes.

17. Gene cloningprocedure A fragment of DNA , containing the gene to be cloned, is cut by enzymes and inserted into a circular DNA molecule (vector) “Recombinant DNA Molecule”. The vectortransports the gene into a host cell (bacteria). Within the host cell the vector multiplies, producing numerous identical copies not only of itself but also of the gene that it carries. The vector must becutwith the same enzyme sothatitcaneasilybind to the DNA of interest.

18. 2) TherapeuticCloning • Process of producinggeneticallyidenticalcellswhichcantreatvariousdiseases. • The clonedcellisused to grownew tissues and/or organs.

19. 3) Reproductive Cloning • Process of producinggeneticallyidenticalorganisms. • This methodisnot verysuccessful, only 0.5-6 % of clonedorganisms are born. • Fromthosethat are bornonly a smallpercentage of them survive. • Manyscientists continue to explore the possibility in order to restore endangeredspecies.

21. Somaticcellnucleartransfer • Boththerapeutic and reproductive cloning use thistechnology to generateclonedcells. • The nucleus of an unfertilizedeggisremoved and replacedwith a nucleus of a somaticcell. • The DNA of the somaticcellis able to direct the development of the recipienteggto formproper tissues and organs.

22. Stem cells: undifferentiatedcellsthatcanreproduceindefinitely and differentiateintospecializedcells. Totipotent stem cells:giverise to any type of cell. Pluripotent stem cells:canproduceonlycertain types of cells.

23. Scnt and stem cells • Stem cellresearch has leadresearchers to move awayfrom SCNT technologies. • Scientistsnow use the following stem cells in hope to repairdamaged or diseaseorgans. a) Embryonic stem cell: totipotent stem cellsobtainedfromembryos b) Adult stem cells: pluripotent somatic stem cellsthat are able to differentiate. c) Induced pluripotent stem cells: stem cellsthat are induced to return to stem-cell-like state.

25. Reproductive technology: Transgenicorganisms • OrganismswhosegeneticmaterialcontainsDNA fromvariousspecies. • Geneticallymodifiedorganisms(GMOs) • Foreign DNA must beinsertedinto the organism in order for this to take place.

26. Applciations of transgenic plants • Plants are continuouslymodified to increaseresistance to herbicides, insects, pests or viruses • Scientists help to use GMOs to increasenutritional value of plants. • Example: Golden Rice

27. Applications fotransgenic plants • Transgenic plants canalsobeused for medicalpurposes • Insulinisnowgrown in safflower plants to produce a lessexpensive version of insulin for people withdiabetes.

29. Applications of transgenicanimals A) Differentorganismsare used to studydiseases and medicalprocedures. B) Transgenicanimals are used to producemedicalproteinsproducts. (e.g. goats- producemilkwithHumangrowth hormone) C) Organismscanbebedevelopped to serve as organdonors to humans.

30. EthicalconcernswithGMos • EnvironmentalThreat: herbicide-resistant plants could encourage the use of stronger herbicides. • Healtheffects: consumingtheseproductscould cause healthconcerns • Social and Economic: the monmeyspentisgreaterthan the overallbenefit.