1 / 18

Human Intervention in evolution

Human Intervention in evolution. Chapter 16. Selective breeding. Artificial selection used to improve herd quality. Select best male to mate with breeding females.

terris
Download Presentation

Human Intervention in evolution

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Human Intervention in evolution Chapter 16

  2. Selective breeding • Artificial selection used to improve herd quality. • Select best male to mate with breeding females. • The deliberate selection by a breeder of specific animals to provide the genetic material for the next generations-Selective breeding. • Contrast of random mating

  3. Artificial Selection • Occurs when breeders favour particular inherited features in their livestock because of their economic value or aesthetic value & use selective breeding to enhance those features & inc. their frequency. • Contrast to Natural Selection as favours aesthetic/economic features, not those for survival/reproduction. • Not necessarily features that good for survival/reproduction • Negative feature stays in gene pool only by humans intervening.

  4. Reproductive technologies-Human intervention Artificial insemination • Involves collecting semen from a stud animal and place it into reproductive tract of female-same species • Inc. no of offspring stud animal can make. Split sperm into 10-put into 10 diff. females. • Freezing involved. • Fertilise more females • Fertilise females that are distant • Fertilise females after dead • Specific allele will become more prominent & alternatives gone • Potential to lose valuable alleles

  5. Oestrus synchronisation • When is possible to predict oestrus cycle of females in a narrow time frame. • Advantages: • Less time needed to test animals to see if fertile • Higher fertilisation rates & birth rates • More manageable and uniform crops of animals • Lower mortality rates of newborns

  6. Reproductive technologies-Human Intervention Sex selection • Chromosome dyed & can see sex chromosome now. X larger than Y chromosome, more DNA so brighter. • Can separate sperm now so sex selected-males. Manipulate breeding cycle • Done through Oestrus synchronisation-become fertile in specific period. • High fertilisation rate • Lower mortality • Managing young easier-same time • Less tests needed

  7. Reproductive technologies-Human intervention Artificial pollination • Involves: • Removal of unripe stamens • Protect stigma of selected female from stray pollen • Collection of desired pollen • Transfer of pollen to stigma • Make new species by mixing pollen & stigma of closely related species. Chemical treatment needed.

  8. Reproductive technologies-Human intervention Cloning-No sex  • Asexual reproduction-DNA from 1 parent only. • Embryo Splitting: cells of early embryo are seperated. Each ind. cell put into uterus of surrogate • Identical ind. Form • Nuclear transfer: remove nucleus from cell (enucleated). • Transfer nucleus from 1 cell into another cell. • Fuse somatic cell with enucleated cell • Downside, low success rate, constant implanations e.g. 1 in 87 eggs fertilised for CC, cloned cat, premature aging because telomere shortens. • Cloning in plants: through cuttings, runners. Cut section or parent plant.

  9. Reproductive technologies-Human intervention Gene Transfer between species • Complete set of genes & non-coding DNA called genome. • Normal transfer of genes-parent to offspring. If unable to because of species ‘species barrier’. • Genetic engineering stops species barrier-manipulates DNA & allows it to be transferred. • Org. with foreign DNA or segment termed transgenic organism. Results in permanent change. • If cell used are prokaryote (bacteria) they’re transformed. • If cell used are eukaryotic, they’re transferred.

  10. GMO • Genetically modified organism (GMO) refers to org. whose genetic makeup has been artificially changed. • Genotype has been modified but doesn’t involve insertion of genes from diff. species. E.g. silencing (switching off) a gene • Transferring genes done by • Micro-injection of DNA, transfer using virus, electric pulse (electroporation)

  11. Gene Therapy • Where a faulty allele in an org. is replaced by the normally functioning allele. • Aim to treat inherited disorders • Wants to add copies of the normal allele of a gene into the cells of a target tissue, turning them on to make the protein missing in the individual.

  12. Stem Cells • Are undifferentiated that have the ability to differentiate into many diff. and specialised cell types: • Nerve, blood, bone, heart • Replace faulty/dead cells • 3 types of stem cells: Totipotent, pluripotent, multipotent (Booklet) • Embryonic stem cells: obtained from inner cell mass of an embryo (Blastocyst). Single cell isolated from inner mass, grown, divide by mitosis & produce stem cells (pluripotent) • Adult Stem cells (somatic): from bone marrow, skin, umbilical cord. Multipotent: can give rise to blood cells.

  13. Cloning • Reproductive cloning- produce a new organism. • Therapeutic cloning- produce stem cells for use in treatment. Done through nuclear transfer technique. Treat patient with spine injury etc… & embryo created is genetic match. • Legislation in Australia has strict controls on embryo use in labs.

  14. Can you imagine a world with… 3 Chong Phat’s 4 DAVID’S…. F*%K!!! 4 DEMI’S!!! 2 Ha’s, Meagan’s & Duyen’s !

  15. Genetic screening • Where DNA sample is analysed to detect the presence of 1 or more alleles associated with an inherited disorder. • Breast cancer gene • Adult screening (test if they transmit disease) • Embryo biopsy: single cell removed to see if fetus is affected • Pre-natal screening: see genetic status of fetus to see inherited disorder present • Predicitve screening: ID a perfon at risk of developing a late onset disease.

  16. Stopping Conception • Production of a zygote & its implementation into the uterus walls called conception-any technique which prevents this called contraception. Overcoming Infertility • Infertility is the inability to conceive or carry a pregnancy to a live birth. • Pelvic inflammatory disease (PID) leads to fallopian tube problems (bacteria) • Several ways to overcome it

  17. Overcoming Infertility Donor Insemination • Fertilise a women with donor sperm (80%). • In-vitro fertilisation (IVF) • Egg is fertilised externally with sperm (can be frozen using cryoprotectant). • Female given artificial hormones to stimulate ovaries. Eggs removed by laparoscope. Sperm added (protein coat removed)= fertilisation. Transferred to mothers uterus at 2-4 cell stage. (20%) • Pg 648

  18. Overcoming infertility Donation of eggs • Egg donated voluntarily by another woman in IVF program. Fertilised with sperm of recipient husband. Surrogacy • Surrogate mother is a woman who agrees to have a baby for another woman. Altruistic-no money involved. • Egg is fertilised using sperm of husband of mother who is unable to have the child.

More Related