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Choices in reproductive Technology. 1. Sex Selection. Choosing to have a baby of a desired sex (gender) No evidence suggesting that natural methods work (position, timing etc ) Pre-implantation Methods: Sperm sorting : (65% - 85% effective)Choose sperm with X or Y depending on preference.
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Choosing to have a baby of a desired sex (gender) • No evidence suggesting that natural methods work (position, timing etc) • Pre-implantation Methods: • Sperm sorting: (65% - 85% effective)Choose sperm with X or Y depending on preference. • Implantation into uterus after IVF • Pre-implantation genetic diagnosis (PGD): embryos from IVF are selected based on gender and then implanted into mother’s uterus. (illegal in some states) • Post-implantation Methods • Sex is determined by ultrasound or amniocentesis (16-20 weeks) • If gender is undesirable couple could have an abortion
Caused by abnormalities in an individuals genes • Four types of genetic disorder: • 1. Single gene disorders (monogenic/Mendelian) • mutation in a single gene causes disorder. e.g. cystic fibrosis, haemophilia • 2. Polygenic Disorders (multifactorial/complex) • mutation in a several genes influence disorder. e.g. breast cancer, arthritis, diabetes • 3. Chromosomal Disorders • Missing or extra parts or whole chromosomes cause disorder. e.g. Trisomy 21 • 4. Mitochondrial Disorders • Mutations in mitochondrial DNA
Prevention • Only way to prevent occurrence is to prevent the birth of a foetus with the disease • Reproductive Choice • Risk of having an affected child may be known and the decision whether or not to have children must also be made based on these statistics • Prenatal diagnosis • Samples of baby’s cells may be taken during pregnancy and analysed. • Parents have the option of an abortion • Sex Selection • Where disease may be X-linked the selection of a particular gender may be appropriate.
Treatment • 1. Prevention of Symptoms • Diagnosis and Treatment before symptoms appear • e.g. PKU • 2. Replacement Therapy • Missing or defective protein is regularly replaced • E.g. diabetes, growth hormone deficiency • 3. Gene Therapy (still in trial stages) • Faulty genes are replaced • a) Germ line therapy: replacement in gametes (difficult technically and ethically
Treatment (cont.) • 3. Gene Therapy • b) Somatic cell gene therapy: replacement in normal body cells • Ex vivo: Cells removed from body, modified gene inserted into cells, cells multiply in a culture (in a lab), then returned to body • In vivo: replaced genes are directly transferred into cell/tissue
3. Gene Therapy (cont.) • Methods of introducing new gene • Viral method: put desired gene in a modified virus (minus disease causing viral genes); allow the virus to ‘naturally’ infect host cells. If host cells are stem cells new DNA is replicated naturally. (eventually host’s immune system will destroy the virus) • Direct Injection: requires large amounts of DNA and only works with some cells. • Liposomes: Put desired gene into liposome (lipid spheres with watery core) which will fuse with target cells membrane releasing DNA into cell. • Artificial Chromosome 47: Introduction of an artificial chromosome which would carry desired genes and be replicated along with regular chromosomes during mitosis. (difficult to place such a large molecule into nucleus)
Breastfeeding vs. bottle feeding • Breastfeeding • Initially contains colostrum: watery, yellow-white fluid, low fat, high antibody concentration • Sterile • Always at correct temp • Correct nutritional balance • More economical • Correct mineral balance • Decreases likeliness of obesity, diabetes and SIDS • Provide some antibodies from mother • Builds strong mother-child bond • Causes mother to release hormones which help to return uterus to normal size • Mother is less likely to develop ovarian or breast cancer or bone loss
Immunity: Resistance to infection by invading micro organisms. • Immunisation: The process of becoming immunised. (Having immunity) • Antigen: a substance which causes an immune response (may be nutrients, toxins produced by a bacteria, whole micro organisms – virus, bacteria, or part of an organism – cell wall, flagella) • Herd Immunity: the general immunity of the population. • Infant Vaccination • Vaccination: giving a person a vaccine, causing an immune response which will reduce the likeliness of a future infection. Results in individual being immunised.
