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Making babies: Genetically Correct. Zhi Hua Ran The department of Gastroenterology Ren Ji Hospital. A Glossary of Genetics Terms. Gene: basic unit of inheritance for all living organisms. Genome: Genetic endowment of a species. Gene mapping: Determining location of genes on chromosome. - PowerPoint PPT Presentation
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Making babies: Genetically Correct
Zhi Hua RanThe department of Gastroenterology
Ren Ji Hospital
A Glossary of Genetics Terms
Gene: basic unit of inheritance for all living organisms
Genome: Genetic endowment of a species
Gene mapping: Determining location of genes on chromosome
Gene sequencing: Determining identity of genes from the distinctive order (sequence) of base pairs, such as A-T and G-C
Chromosome: Threadlike structure in the nuclei of plant and animal cells; it carries the linearly arranged genetic units (genes)
A Glossary of Genetics Terms
Nucleic acid: Large, chainlike molecule of phosphric acid, sugar and purine and pyrimidine bases
Marker: Gene with a known location on a chromosome
Template: Macromolecular model for another macromolecule, as in the synthesis of RNA from a DNA template
Transgenic: Organism, such as a mouse, containing experimentally transferred genetic material from another organism, such as mammal
Mutation: Abrupt change in the genotype of an organism that is not the result of recombination
A Glossary of Genetics Terms
Recombination: Formation in offspring of genetic combinations not present in parents
Genotype: The genetic constitution of an individual
Phenotype: The observable characters of an organism; the result of the way the genes are expressed
Genetic defect: Pathological changes that occur by duplication, deletion or rearrangement of DNA
Transcription: The process by which RNA is formed from DNANucleotide: The structural unit of nucleic acid
A Glossary of Genetics Terms
RT-PCR: Reverse transcriptase polymerase chain reaction
Gene therapy: A technique for correcting defective genes responsible for disease development
DNA microarray: An experimental tool for obtaining high-throughput gene expression data
Stem cell: have the remarkable potential to develop into many different cell types in the body. Serving as a sort of repair system for the body, they can theoretically divide without limit to replenish other cells as long as the person or animal is still alive. When a stem cell divides, each new cell has the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.
Milestones of Genetics
Discover the double-helix structure of DNA---by James Watson and Francis Crick
Mapping the human genome---The Human Genome Project, completed in 2001
Create the first recombinant DNA molecule---by Paul Berg
Discover the DNA structure
1953---James Watson/Francis Crick
Double-helix structure of DNA
Biography---James Watson
Born in Chicago, April 6, 1928 His father‘s ancestors were originally of English descent His mother‘s father was Scottish-born taylor married to a daughter of Irish immigrants who arrived in the US about 1840Spent entire boyhood in Chicago
Biography---James Watson
Study at University of Chicago at 1943
In 1947, received a B.Sc.degree in Zoology During these years, his boyhood interest in bird-watching had matured into a serious desire to learn genetics
His Ph.D thesis was a study of the effect of hard X-rays on bacteriophage multiplication
In 1950, received Ph.D degree in Zoology at Indiana University
Biography---James Watson
In the spring of 1951, he change his direction of his research toward the structural chemistry of nucleic acids and proteins
Met Crick at 1952, common interest in solving the DNA structure
Solved in early March, 1953---the proposal of the complementary double-helical configuration
1953~1955 at the California Institute of Technology as Senior Research Fellow in Biology 1956, Assitant Professor, Harvard Biology Department
1958, Associate Professor
1961, Professor
Biography---James Watson
1962, The Nobel Prize in Physiology or Medicine
Born on June 8, 1916 at Northampton, England
In 1937, obtained a B.Sc. In Physics at London
During the war, he worked as a scientist for the British Admiralty
Biography---Francis Crick
Left the Admiralty in 1947 to study biology
Started to learn biology in 1937, interrupted by World War Two
Joined the Medical Research Council Unit since 1949
Restarted in 1950, obtained Ph.D in 1954
Biography---Francis Crick
1962, The Nobel Prize in Physiology or Medicine
Died at 2004
Worked out the general theory of X-ray diffraction by a helix
Born on June 30, 1926, New York
Biography---Paul Berg
Best known for his development of a technique for splicing together DNA from different types of organisms.
His achievement gave scientists a tool for studying the structure of viral chromosomes and the biochemical basis of human genetic diseases.
Gained early recognition/influence when he delineated the key steps in which DNA produces proteins
Awarded the Nobel Prize for Chemistry in 1980
The Human Genome Project
Began at 1990
Draft sequence was published in 2001
Founded by US department of Energy (DOE), US National Institute of Health (NIH) in collaboration with Britains Wellcome trust
The Human Genome Project
Celera Genomics, a private company based in Maryland, is publishing its findings in Science.
Human have about 30,000 genes
A public international effort, led by the United States, is publishing its analysis of the genome in Nature, a British journal.
Genetic differences between any two people are relatively small
The Human Genome Project---more powerful tools
Durg development, customizing drugs to individual genetic profiles
Earlier diagnosis of disease
In Vitro Fertilization---history
The technique was developed in the UK by Dr. Patrick Steptoe and Robert Edwards
First “test tube“ baby: In UK, Louise Brown (July,1978
The first in US: Elizabeth Carr by Dr. Howard and GS Jones (1981)
Second “test tube“ baby: In India, Kanupriya Agarwal by Dr. Mukhopadhyay (Oct, 1978)
Since then, IVF has exploded in populatiry, accournts 1% of all birth, 115,000 in total in US
The first “test-tube “ baby
In Vitro Fertilization---history
Louise Brown born in England in July 25, 11:47 PM, 1978
25 y
1y
With parents
In Vitro Fertilization---history
Oldham General Hospital
Dr. Patrick Steptoe
Dr. Robert Edwards
At birth
In Vitro Fertilization
The first phase consists of stimulating the ovary with hormones injected, in order to cause several eggs to mature
Normally, only one egg matures per menstrual cycle, so additional hormones are usually required to prevent the body from negatively to this excess of eggs
Phase 1:
The last injection given is that of human chorionic gonadotropin (hCG), the hormone normally produced during pregnancy
In Vitro Fertilization
The second phase, that of egg retrieval, occurs about 34-36 hours after the hCG injection
The entire procedure usually takes8-20 mins
Phase 2:
In Vitro Fertilization
The third phase involves fertilization of the eggs
Phase 3:
ICSI---Intracytoplasmic sperm injection
1
2
3
In Vitro Fertilization
Phase four is the actual embryo replacement
A pregnancy test usually is done 12-14 days after retrieval
Phase 4:
2 Cell embryo 4 Cell embryo 8 Cells embryo
Thumbing through the encyclopedia of life
Technology often drives science, science drives medicine, and medicine is always pushing society
in to ethical corners
Dr. Mark Hughes
Prenatal Genetic Analysis
One of the ethically most problematic applications of genetics
If detected in the fetus, are incurable, may lead to selective abortion
Prenatal diagnosis of genetic traits typically can only provide information to assist the prospective parents in their decision making whether to carry the pregnancy to term or to terminate it
Prenatal Genetic Analysis
It requires both a medical indication and informed conset of the parents
Parents have a right to refuse medically indicated prenatal diagnosis even if there is a high risk for fetal condition that is incompatible with life
There are a few genetic traits (such as gender) are accessible to prenatal diagnosis today but unrelated to health
Prenatal Genetic AnalysisPrenatal diagnosis is carried out only to give parents and physicians information about the health of the fetus
The use of prenatal diagnosis for paternity testing, except in cases of rape or incest, or for gender selection, apart from sex-linked disorders, is not acceptable
WHO 1998
Prenatal Genetic AnalysisHeterozygosity testing for recessive disease could only be attempted for eugenic purposes
Gregor Mendel 1822~1884
Mendel‘s law of independent assortment孟德儿独立分配定律Mendel‘s law of segregation孟德儿分离定律
Novel parameters for prenatal selection--- gene testing
Carrier screening, which involves indentifying unaffected individuals who carry one copy of a gene for a disease that requires two copies for the diasese to be expressed
Preimplantation genetic diagnosis (screening Embryos for disease)
Newbone screening
Presymptomatic testing for predicting developing adult-onset disorders such as Huntington‘s disease
Presymptomatic testing for estimating the risk of developing adult-onset cancers and Alzheimer‘s disease
Confirmational diagnosis of a symptomatic individual
Forensic/identity testing
Gene testing---HD
Huntington‘s disease (HD):Usually midlife onset; progressive, lethal, degenerative neurological disease
Caused by a single abnormal gene
An autosomal dominant disorder
Gene testing---SMA
One of the neuromuscular diseases. Muscles weaken and waste away (atrophy) due to degeneration of motor neurones which are nerve cells in the spinal cord
Gene was located Proximal portion of the long arm of chromosome 5 , 1990
Gene testing--- Fanconi Syndrome
A disorder in which the proximal renal tubules of the kidney do not properly reabsorb electrolytes and nutrients back into the body
Excessive drinking, urination and glucose in the urine
Muscle wasting, acidosis and poor condition will also occur
Pre-implantation diagnosis
Single cell analysis
Technology: RT-PCR
Technology --- RT-PCR
Electrophoresis
DNA microarray
Gene therapy
A normal gene may be inserted into a nonspecific location within the genome to replace a nonfunctional gene. This approach is most common
An abnormal gene could be swapped for a normal gene through homologous recombination
The abnormal gene could be repaired through selective reverse mutation, which returns the gene to its normal function
The regulation of a particular gene could be altered
Dr. Mark Hughes
A Professor and Director of Molecular Medicine and Genetics at Wayne State University and Director of the Genomics Center Hub for the State of Michigan's Life Sciences Corridor.
His work has centered on understanding gene expression in the early human embryo
He pioneered the field of PGD for couples at very high reproductive genetic risk and offers this technology in conjunction with IVF Centers in the U.S. and Canada.
Bypassing the natrual method of conception
Discarding excess embryos
Contributes to overpopulation
Ethical challenges
Creating life in the laboratory
Fertilizing more embryos than will be needed
Unnatural environment for embryos
Potential to select embryos
Potential to modify embryos
Ethical challenges
Potential to creat embryos for medical purposes
Alteration of genetic traits:Beauty/handsome, longevity, healthy
Potential to modify embryos
A girl or boy, you pick?
Potential to select embryos
We can test for lots of things, the question is,
should we?
--- Dr. Mark Hughes
Ethical challenges