IB Biology Chapter 3-Genetics.

IB Biology Chapter 3-Genetics

_____________________________=science of how inherited info is passed fron one generation to the next by using genes and DNA Genetics

I.Genes What is a gene? Heritable factor that consists consists of DNA and influences a specific characteristic Heritable-________________________________________________________________________________ The estimated 21,000 genes we have are organized into chromosomes Passed on from parent to offspring,and characteristic refers to genetic traits,such as eye color

A. A gene is a particular locus on a chromosome
Gene for a specific trait occupies a specific location-LOCUS Geneticists map out the locus of each sequence Of particular significance for research if they find a specific sequence controls a heritable factor eg. They have found that a locus of a gene controls protein______________________that allows for color vision on chromosome #1.A mutation of this gene stops a person from making this protein properly,thus a person will not see color-achromatopsia being able to see color actually means 2 things- 1-that person has DNA code for making color vision possible or 2-they not have the genetic code for that transducin

The locus is the specific position of a gene on a c’some

2 copies of each gene in body-same same locus on other chromosome-one from mom and 1 from dad-not necessarily identical -genes come in different forms

B. Alleles:versions of genes
Alleles-variations/versions of genes-specific form of gene,differing from other alleles by 1 or a few bases w/transducin, a single base pair sequence between most common allele(C at position 235) and the rare mutated the same position)-all the difference that decides whether you can see color allows for variants in traits

Cystic fibrosis difference between 2 alleles for a single trait is the difference that causes cystic fibrosis a gene called CFTR-on chromosome 7-plays key role in production of mucus standard version allows mucus-producing cells to function properly mutation of CFTR gene causes Cystic Fibrosis-abnormally excessive qty of mucus in various organs-esp. respiratory and digestive systems

C.One base can make a difference-
Importance of every letter of genetic code be in proper place,one sm difference can be critical Gene-ABBCC11-determines whether-cerumen-ear wax-wet(amber) or dry-also flaky or grey-decided by gene on chromosome 16-G=dry ear wax (European and African)-A variant(wet) among Asians This can reveal a lot about how populations have migrated and reveal items relevant to health Same gene also involved with underarm sweat and breast milk-possible link to breast cancer

How new alleles are formed
example p.117 RNA sequences from p.117: 1-GUG GAC CUG ACU CCU GAG GAG 2-GUG GAC CUG ACU CCU GUG GAG sequence 1-valine-histidine a)_________b)________c)_______d)_________-glutamic acid sequence 2-valine-histidine e)_________f)_________g)_______h)________glutamic acid use genetic code to solve the above this will change the structure of resulting protein-mutation

Mutations Random,rare change in genetic material
1 type involves change in DNA sequence,which should not happen if replication works,but such mistakes occur in nature—eg.T may replace A-affects transcription-can be a positive or negative effect

Are mutations good or bad for us?
LRP5-gene that helps immune system make certain protein that acts as a receptor on their surface/research indicates it is used by HIV to infect cells Those that have mutation of this gene cannot make this receptor protein and HIV CANNOT infect them-naturally immune---a rare mutation A mutation that increases chance for survival has a better chance for being passed on to next generation,whereas detrimental ones are less likely to be inherited-since they decrease chances for survival When mutation successfully passed on it becomes a new _______________-new version of original gene We all have mutations-whether harmful,beneficial,or neutral depends on the gene and the environment in which you are required to survive allele

A gene to help digestion-
We have mostly been hunter-gatherers and genes are adapted for this life We mostly had only drank milk-as mammals-at infancy,so adults have become lactose intolerant and still prevalent today(>50% of population) However,past 10,000 yrs we have developed an agricultural –based lifestyle-consuming milk as adults,and many such societies have shown an increase of those that tolerate lactose-increasing our evolved ability to survive harsh climatic change Read about gene therapy on p.120

Base substitution mutation-
Results in a single letter being changed Could change amino acid which may or may not be major effect

Sickle-cell disease(sickle-cell anemia)-
Mutation for gene that codes for hemoglobin on RBCs in humans(base substitution mutation) Gives different shape to molecule-curved sickle shape rather than biconcave disk 6th codon in sequence of hemoglobin is _____,rather than GAG-instead of glutamic acid,valine instead hemoglobin will have different properties(valine has a different shape and properties) symptoms--________________________-O2 cannot be carried as well by sickle-shaped RBC’s the different hemoglobin also tends to crystallize w/in blood cells-so less flexible-get stuck in capillaries-slowing or stopping blood flow-great pain GTG Weakness,fatigue,shortness of breath

The advantages of sickle cell disease
resistant to malaria infection caused by ________________mosquito carrying______________________. attacks RBCs-high fever ,chills,possible death we carry 2 genes for RBC shape-standard shaped RBC higher chance of getting malaria people w/ 1 gene for sickle shape and 1 normal have____________________both shapes in their bloodstream and usually do not have sickle-cell disease Anopheles Plasmodium Sickle-cell trait

have better resistance to malaria because_____________________________.
insufficient amounts of ____________ in sickle cells cause Plasmodium to die people w/ sickle cell disease have highest resistance to malaria K Of chemical imbalances that make the survival of Plasmodium in blood more difficult

D. A genome although we have mapped many genes,b there remains much mapping yet to do and many sequences for which we do not know function Sequencing DNA scientists have highly specialized sequencers to locate and ID bases complete set of any organism’s base sequence is its ____________________. billions of bases –yet found in any typical cell in your body the complete genomes of some organism have been found-eg-Drosophila melanogaster and Esherichia coli,because used so much in bio labs genome

Summary of __________________technique to completing a genome:
Sanger 1-Once DNA is obtained,copied and copies of fragments made-_________________ 2-To determine sequence-_________________________ attaches to one copy of 1st fragment(we’ll call it fragment 1).It will start to add free nucleotides by ____________________________ kinds of nucleotides added 3-Some nucleotides standard,but some special dideoxynucleotide triphosphates(ddNTP labeled ddA,ddT,ddC,ddG-figure 3.7-p.123)-added as DNA chain terminators-means that ______________________________________-previously marked w/florescent markers to ID.Chain termination may happen all way to end of fragment 1-but usually it stops before the end-happens on each of many copies of fragment 1 A DNA polymerase enzyme When 1 is reached,the elongation of the strand is stopped A primer sequence is added to help start the process The principle of complementary base pairing

Sanger Technique cont’d
4-result is a series of new strands(maybe dozens of bases long,some a few less,some w/ all the bases of fragment 1) 5-ready for sequencing:multiple chains of varying lengths(ea w/florescent marked end) put in order from longest to shortest-done by using __________________________________. 6-________________________________________________________________________________________________ To recognize ea letter,laser activates florescent markers on nucleotides as they go through the process.A sensor hooked up to a computer analyzes the wavelength of light and determines whether A,T,C,G Gel electrophoresis

Sanger cont’d 7-process repeated many times-for A.T,G,and C—to ensure no errors(there will be many copies fragment 1 so that can be checked) 8-when fragment 1 is done,the lab technicians must process fragment 2,3,etc…until all fragments of original sequence processed 9-Now need to put all sequenced fragments of code together-When original sequence was chopped up-mixed up and out of order….now knowing sequence,we will know their order---basically lining up any overlapping segments until all match since this technique developed many ways have been developed to analyze ea fragment only 1x-so don’t have to make multiple copies-reduces time and cost

Be sure to see p.123!

Human Genome Project 1990 this cooperative task was began to catalogue all the bases in human DNA 2003-declared goal reached now the work is to determine which sequences are genes and which are not human genome shows locus of any gene on any 1 of 23 prs of chromosomes before the project,< 100 loci for genetic diseases known,after-> 1400 known---now 1000’s and increase by comparing genetic makeup around the world,it tells a lot about ancestries ,migrations,and mixing of genes in populations over time

Using DNA to make medicines
steps: 1-find beneficial molecules that are produced naturally in healthy people 2-find out which gene controls synthesis of desired molecule 3-copy that gene and use instructions to synthesize molecule in a lab 4-________________________________________ eg.-genes controlling aging-think about ethical and financial implications Distribute the beneficial therapeutic protein as a new medical treatment

Can human genes be patented?
2013-US supreme court decided on case – AMP(Association for Molecular Pathology v. biotech company(Myraid Genetics) –Myriad had patent on BRCA genes(breast or ovarian cancer)-AMP felt BRCA gene sequences should be available freely for diagnostic purposes-Myriad said since the genes occur naturally-since found in nature all genes connected to each other but scientifically accessed so can be patented---plaintiff said this made it impossible to get 2nd opinion….Supreme court said unconstitutional to patent DNA sequence found in nature

II. Chromosomes- A. The chromosome in prokaryotes
single,long continuous,circular thread in nucleoid region only 1 c’some because only 1 parent

Some prokaryotes also have plasmids but eukaryotes do not
Escherichia coli and others have small loops of DNA that are extra copies of some of the genetic material=plamsids not connected to main c’some replicate independently of c’somal DNA not req’d by cell under normal conditions,but can help cell adapt in unusual circumstances also found in Archae used in genetic engineering not in eukaryotes

C. Eukaryote chromosomes
usually DNA in form of c‘somes info for cell’s existence not visible when cell is not this point.Chromatin made of________________________. unfolded DNA in electron microscope looks like string of beads-Ea of the beads being a ____________________________ Nucleosome consists of __________________________________ nucleosome Strands of DNA and proteins called histones 2 molecules of each of 4 different histones

DNA wraps 2x around 8 protein molecules
DNA attracted to histones because______________________________________ between the nucleosomes is single strand of DNA There is often a 5th type of histone attached to the linking string of DNA near ea nuclesome.5th histone leads to more wrapping-_____________- of DNA and finally to a highly condensed or supecoiled chromosomes when DNA is wrapped around histones and even further wrapped it is _______________________________________________.So,wrapping or packaging regulates transcription-allowing only certain areas of DNA to be involved in making proteins In elaborate structures,it is inaccessible to transcription enzymes DNA is negatively charged and histones (+) packaging

D.Multiple chromosomes

E.Homologous chromosomes: the same genes but not always the same alleles
humans have 23 pairs of homologous c’somes-homologous means _____________________________________ Similar in shape and size & means that the 2 chromosomes carry the same genes

There are 2 c’somes because 1 from each parent,but not identical because alleles for genes can differ locus contains different bands in picture(see color on ppt) showing 1 allele from mom and 1 from dad the c’somes pictured are doubled because of replication-They only look like this when ready to divide-2 sister chromatids ________________________ and after division will be 2 separate identical c’somes centromere

F. Diploid and haploid cells
_____________________-describes a nucleus w/c’somes organized into prs homologous c’somes most in human body diploid w/23 sets from ea parent,ie. 46 total gametes are ________________ and contain 1 c’some from each pair adult animal cells rarely haploid-exception male bee,wasp,and ant haploid usually only gametes are haploid diploid Sex cells

n -_____________________________________
for a human egg,n=23 __________________ are fertilized eggs and are 2n,2n=46 in humans Represents haploid # and refers to # sets of c’somes that a nucleus can have

G. Chromosome number: a defining feature
usually # of c’somes is a characteristic feature of the cells of a species(exception-RBCs) and some anomalies, such as Down’s Syndrome Caenorhabditis elegans-worm well studied-genome sequenced in 1998(6 c’somes---n=3)

H. Karyograms and karyotypes
__________________-representation of c’somes in a cell arranged in standard format-in order by size and shape-shape depending mostly on position of centromere a karyogram shows a person’s __________________-specific number and appearance of c’somes in his or her cells cells obtained from amniocentesis or chorionic villus sampling are grown in culture and karyogram made by the following steps: 1-cells stained and prepared on slide for examination under light microscope 2-photomicrograph images are obtained of c’somes during mitotic metaphase 3-images are cut out and separated-w/scissors or by computer 4-images of ea pair placed in order by size and position of centromeres.Generally,by decreasing length(except sex c’somes in male-XY) karyogram

I. Sex determination autosomes 23rd pr sex c’somes
x longer than y w/many more genes/only pr of c’somes w/different sizes and shapes female=XX- each gamete will have 1 x male=Xy and ½ gametes get x and ½ get y therefore 50% chance of boy or girl offspring non sex c’somes are called _________________________________________-.Humans have 22 pr of autosomes if a trait or gene is described as autosomal,its on prs 1-22 when a gene is more common in 1 gender,good chance it is sex-linked-either on y or x autosomes

Autoradiography technique in which radiation from a substance is captured on photographic film or by camera sensor autoradiograms are exposed to radiation coming off of substance itself DNA describe as “taking its own pictures”-used to get images of DNA strands so length can be measured ____________________________-produced by injecting radioactive materials into DNA samples that will expose the film faster-such materials called ______________________________ in measuring lengths of DNA strands,the DNA forming during replication is given a radioactive form of thymidine,which is ______________________________________________________. radioactive form added in the experiment is called 3H-thymidine(3 is radioactive isotope of H)-used as radio marker to keep track of where thymidine molecules are-which leaves traces on photographic film _________________(1862) used this technique to demo that a bacterium’s c’some is made of a single circle of DNA replicated by being unzipped-He called the images theta structures A component of a DNA nucleotide made up of a pentose sugar bonded to thymine Cairns’ Technique John Cairns Radio markers

IV. Inheritance A.Mendel’s experiments with pea plants
Who was Gregor Mendel ? (1865)-monk –published results on pea plants and how they passed on that time genes were not yet known-He used term-factor-DNA not discovered Questions he had: How can I be sure I will get smooth peas and not rough ones? How can I be sure the resulting plants will be short or tall? How can I be sure to obtain only flowers of a certain color?

Key Terminology Genotype-_____________-eg-Bb,GG
Phenotype-characteristics or traits of an organism-eg-hair color Dominant allele-an allele w/same effect on phenotype whether homozygous or heterozygous-eg- Aa with trait from A expressed-a is masked-not transcribed or translated Recessive allele-an allele w/ effect on phenotype only if homozygous,eg-aa showing recessive trait because no dominant allele to mask it The symbolic representation of the pr of alleles an organisms has,usually shown by 2 letters

Co-dominant alleles-_____________________________________
eg-curly x straight producing degrees between 2 traits-both alleles influence ________________-particular position on homologous c’somes of a gene-ea gene has a specific place on a specific pr. of c’somes Prs of alleles that both affect the phenotype when in a heterozygous Locus

Homozygous-having 2 identical alleles of a gene-eg-AA,aa
Heterozygous-having 2 different alleles of a gene-due o paternal allele is different from maternal one…eg-Aa

Carrier-____________________________________________
eg-Aa-carrier for albinism- but has pigmented skin,thus ancestor must have been albino and offspring might be _________________-testing suspected heterozygote plant or animal by combining w/known homozygous recessive-Since recessive allele can be masked-it is often impossible to tell if homozygous or heterozygous dominant unless offspring shows recessive trait Test cross An individual who has a recessive allele of a gene that does not have an effect on phenotype

B.Gametes only have 1 allele of each gene
Constructing a Punnett grid- -used to show how the alleles of parents are split between gametes and how new combinations of alleles can show up/shows all possible combinations in a mono hybrid cross-parents have different alleles and only shows 1 trait

C. The two alleles of each gene separate
tracing inheritance using albinism as example/to set up Punnett grid: 1-Choose letter to show alleles/capital-domiant and lower case-recessive(A and a)/do not mix letters(like a P and an A) 2-Determine parents genotypes(homozygous dominant heterozygous,or homozygous recessive) 3-Determine gametes parent could produce 4-Draw a Punnett grid 5-Work out the chances of each genotype and phenotype occurring -ea grid shows 1 of 2 possible statistics-ea square 25% - the probable proportions only work for large #’s of offspring Big letter goes before small in heterozygous

D. Fusion of gametes The results should be referred to as 50% chance in humans –whereas 50% offspring in plants,which produce much more offspring -each offspring result of gamete fusing-make zygote deduce phenotype from genotypes----eg Aa-normal pigmentation/aa-albino

E. Dominant alleles and co-dominant alleles
Short or tall pea plants Mendel crossed purebred tall w/ purebred short(purebred-known to be all tall or all short)-question was would he get all tall,some tall ,both,or all short took months to confirm-but we can predict in seconds w/grid-Because tall dominant over short F1(1st filial) shows results to cross F2- %chance of tall/25% chance of short….the talls have differing genotypes In a real experiment,unlikely exact results---due to chance…if there are hundreds of results---will be close to predicted

75%chance of tall/25% chance of short…
75%chance of tall/25% chance of short….the talls have differing genotypes In a real experiment,unlikely exact results---due to chance…if there are hundreds of results---will be close to predicted

Test cross If a plant breeder needed to know if a specific tall plant from F2 is a purebred tall---They would do a test cross---test 1 in question w/ 1 whose genotype is known…If they get a mix of tall and short—the tall is heterozygous(if crossed w/tt),but if all are tall then homozygous Possible,but unlikely is that that 1 gene never passed on…unlikely esp w/many offspring

Multiple alleles sometimes 3 or more alleles for same gene-eg.ABO blood typing

Blood Type: an example of multiple alleles
ABO blood type system has 4 possible phenotypes:____________/3 alleles of a gene gene represented by letter I(I and i) and superscripts used to show 3 alleles 6 genotypes give rise to 4 phenotypes A,B,AB,and O

6 genotypes codominance
The heterozygous shows____________________-neither allele is masked and blood type is AB codominance

Autosomal genetic diseases in humans
Autosomal recessive diseases-on 1st 22 prs of c’somes-not sex c’some albinism,cystic fibrosis,phenylketonuria(PKU),sickle cell disease and sickle cell trait ,Tay Sach’s, thalassemia Genetic diseases are rare even most common 1 in 2000

Diseases caused by sex-linked genes or co-dominant alleles
Genes carried on sex chromosome because y much smaller than x, fewer loci-fewer genes often a gene on x, has nothing to pair up with on y-esp. if extremity of x

Sex linkage- sex-linked-_________________often affect 1 sex more than the other-eg-colorblindness and hemophilia color-blindness-__________________________ Any trait having gene locus on X or Y Inability to distinguish between certain colors-often green and red-those colors will look the same

Hemophilia _____________________________
Blood does not clot properly-treated w/ injections

The pattern of inheritance with sex-linked genes
Carriers of sex-linked traits-rare in most human populations worldwide-so recessive case very unusual-so few women have these traits males either have or do not –will not be carriers more sex-linked traits-___________________ Duchene Muscular dystrophy , wt-eyed fruit flies , calico/tortoiseshell cats

Some possible causes of mutations,genetic diseases and cancer
-in principle-DNA not to be modified and code should be preserved,but radiation and carcinogens can modify code and cause disease Other causes of cancer and disease mutagenic chemicals-eg.benzene radiation many regulated by government standards not all people follow recommendations repeated exposure

DNA and radiation eg-Marie Curie-leukemia victims of atomic bombs When radiation hits DNA molecule,may_______________.This causes a mutation –may be benign or harmful nuclear power plants-Chernobyl(1986),Fukushima(2011)-radioactive material leaked out ecologists studying these sites w/ varying results dome of Chernobyl as possible deterrent from leaking radiation knock out 1 or more base pairs-out of place-modifying genetic code-causes a mutation-benign or harmful

Genetic modification and biotechnology
A.Exploring DNA genetic techniques that enable scientists to explore and manipulate DNA: copying DNA in a lab-______________ using DNA to reveal its owner’s id-DNA profiling __________________________________ _cutting and pasting genes to make new organisms-gene transfer cloning cells and animals new hopes for treatments and vaccines for diseases creating new plants for farmers freeing those wrongfully imprisoned gene transfer and cloning sparked debates-re-manipulation of nature,cost and profiteering ,ethics of human clones PCR Mapping DNA by finding where every A,T,C,G is-gene sequencing,inc.Human Genome Project

Gel electrophoresis separate fragments of DNA to id origin
enzymes used to____________________ DNA fragments placed into small wells(holes) in gel, one end gel exposed to electric current-(+ ) on one side and (-) on other __________________do not move easily, getting stuck close to beginning Chop up the long filaments of DNA into varying sizes of fragments The biggest,heaviest ,and least charged particles

Gel electrophoresis cont’d
____________________pass through gel to other side w/little problem intermediate particles –distributed-in between leave a banded pattern-in the end-see photo gel electrophoresis can stop there or a hybridization probe can be added.A probe for sickle cells,(SEE EXAMPLE IN BOOK) a known sequence of complementary DNA sequence that binds w/ a DNA strand in the gel, presenting gene sought The smallest, least massive, and most charged particles

Autoradiogram above

PCR:how to make lots of copies of DNA
Polymerase chain reaction(PCR) PCR=lab technique using a machine called a thermocycler that ________________/is used to solve problem of how to get enough DNA to be able to analyze it-CSI and other sampling sources typically have a limited quantity of cells/PCR accomplished in a few hrs to analyze-usually by gel electrophoresis Takes a very small quantity of DNA and copies all nucleic acids in it to make millions of copies of the DNA

D. DNA profiling process of matching an unknown sample of DNA with a known sample of DNA to see if they correspond also called DNA fingerprinting significance of identical fragments and similar fragments

Applications of DNA profiling
paternity suits suspects and crime scene blood and semen use gel electrophoresis used in ecosystems-to clarify relationships-social relationships,migrating patterns,nesting habits,evolution by indicating common ancestry

How DNA profiles are analyzed
similarities may indicate family relationships technique perfected so that rather minute quantities of samples yield adequate data

Gene modification :gene transfer between species
technique of taking gene out of one organism(donor-eg. a fish) and placing in another (host-eg.-a tomato) the above example was done to make tomatoes more resistant to cold and frost since DNA based on universal code it is possible to________ One species’ genes into another genetic makeup

Bacillus thuringiensis
all known organisms use the bases A,T,C,G to code for proteins-so transferred DNA codes for same polypeptide chain in host as it did in donor—based on same amino acids-eg.same proteins used by fish to resist arctic waters are used by tomatoes to be resistant to cold eg.-Bt born,genetically engineered to produce toxins that kill the bugs that attack it/the gene(and name) came from ____________________________,which has ability to produce a protein fatal to larvae of crop-eating pests consider questions and problems with gene modification-see p.161 Bacillus thuringiensis

Clones Restriction enzymes
cutting,copying,and pasting genes cutting and pasting DNA- “scissors” used are ____________ called endonucleases,which find and recognize specific sequence of base pairs along DNA molecule some can target____________ Restriction enzymes Sequences that are sets of 4 base pairs,others locate 6 pairs

cutting and pasting DNA-cont’d
endonucleases cut DNA at specified points if both beginning and of a gene are cut out,gene is_____________________ for pasting genes,the enzyme is _________________________-recognizes parts of base sequences that are supposed to link together-called__________________ and attaches them Released and can be removed from donor organism Sticky ends DNA ligase

Copying DNA(DNA cloning)
more complex-because_________ yeast can used,but most popular is _____________ like other bacteria,most of genetic info for E. coli is on a single c’some,but some is found inlamids-small circles of DNA in cytoplasm E.coli A host cell is needed in addition to the cutting and pasting enzymes as described

DNA cloning using E.coli cont’d
like other bacteria,most of genetic info for E. coli is on a single c’some,but some is found in plasmids-small circles of DNA in cytoplasm to copy a gene-it must be ___________________ To do this,plasmid removed from host cell and cut open using restriction endonuclease gene to be copied is placed inside open plasmid-called_______________ gene is pasted into plasmid using DNA ligase plasmid now called recombinant plasmid and be used as a vector-tool to intro new gene into organism’s genetic makeup Gene splicing Glued into plasmid

see also p.162-drawing is simplified

process been used to get E.coli to make human insulin
final step- for copying(or cloning) the gene-________________________________________ accomplished by putting bacterium into a bioreactor-vat of nutritious warm temp host cell makes copies of gene as it reproduces and gene is now in its genetic makeup-modified E. coli expresses gene and synthesizes whatever protein the gene codes for. process been used to get E.coli to make human insulin The vector is now placed inside host bacterium and bacterium given ideal conditions to grow and proliferate

GMO’s GMO-artificial genetic change made to organism using techniques of genetic engineering(gene transfer or recombinant DNA) main reason is to be competitive in food market also to teach bacterium to produce medically useful proteins ,as w/insulin

Transgenic plants simplest kind of GM food is one in which undesirable gene HAS BEEN REMOVED,sometimes more desirable in its place,or just intro a new gene-so then ,no DNA removed ultimate end result is either organism no longer shows undesired trait or shows a new desired trait 1st commercial example Flavr Savr tomato(1994-sold in USA)-modified to delay ripening and rotting,so stay fresh longer company lost a lot of $ on this another species tomato modified to be more tolerant to salinity-so-they proposed-would help solve world hunger GM rice made to produce beta carotene-so to help the consumers not be deficient in vitamin A

Transgenic animals eg,for medical treatment w/ hemopihila ,victims lack a clotting factor like factor IX-can be produced in GM sheep that secrete through milk(proposed) other implications

Natural methods of cloning
certain plants-like strawberries,send out horizontal structures to allow a new strawberry plant to grow nearby-exact genetic copy of 1st plant-w/o meiosis or fertilization potato grown from an original planted advantage to plant of ease of avoiding pollen route-but if one potato susceptible to blight,then all clones will be(re-Ireland 19th century) rare among animals-except some invertebrates-eg.Hydra vulgaris-budding/hydra can also sexually reproduce

Animals cloned from embryos
clone=group of genetical id organisms,or grp of cells artificially derived from 1 parent results from a lab technique in farming-occurred for decades in regenerating plant material or in vitro fertilization (naturally in humans as id twins) 1st evidence of attempt (1890)-Hans Dreisch-_______________________________________________his intent was not to create clones-serendipity-re-sea urchin emryos w/correct lab equipment-we can separate cells from a growing embryo and place in uterus of an animal-remember embryonic cells are undifferentiated --so not remarkable cloning-artificial twins w/sea urchins-He separated cells from a single sea urchin emryo and grew 2 id embryos

See handout on history of cloning and artificial twinning

Animals cloned from adult cells
Clones and cloning previously only possible from fertilized egg-after much dividing, specialize into muscle ,etc—it was thought after differentiation ,could not clone….but HELLO DOLLY!!!!

Cloning using a differentiated animal cell
1996-Ian Wilmut-Dolly the sheep-1st such clone ____________________ An unfertilized egg collected from another sheep and its nucleus removed using electrical current,egg cell and nucleus from cultured somatic cell fused new cell developed in vitro in a a similar way to a zygote,and started to form embryo embryo placed in surrogate womb mother sheep dolly born-clone of original donor sheep From original sheep to be cloned-somatic cell from udder was cultured and collected-Its nucleus was removed!

this is _______________________cloning-because makes entire individual
technique is__________________ Reproductive cloning Sometimes called SOMATIC CELL NUCLEAR TRANSFER

Cloning using undifferentiated cells
to make copies of cells called _____________________________________ cells referred to as embryonic stem cells/involves stem cell research Therapeutic cloning-aim is to develop cells that have not gone through differentiation-

Ethical issues surrounding therapeutic cloning
problem arises because starts w/ making a human embryo has lead to major breakthroughs/aims: skin to repair burn new heart muscle new kidney tissue

IB Biology Chapter 3-Genetics.

Similar presentations

Presentation on theme: "IB Biology Chapter 3-Genetics."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

IB Biology Chapter 3-Genetics.

Similar presentations

Presentation on theme: "IB Biology Chapter 3-Genetics."— Presentation transcript:

Similar presentations

About project

Feedback