Human traits and gene therapy

1. Human traits and gene therapy

2. A pedigree is a graphic way to look at a trait between ancestors. • It shows how a trait is passed between each direct member of the family. It can be used to see where a trait came from or if you have a chance for a disease.

3. Simple recessive traits • Most genetic human disorders are caused from recessive traits. We have removed them from the gene pool. • Cystic fibrosis- caused by a defective protein in the plasma membrane. • Tay-Sachs disorder- causes damage to the central nervous system because an enzyme is not produced and can not break down certain lipids in the cell • Phenylketonuria- can cause mental retardation and damage central nervous system because of a missing enzyme

4. Simple dominant traits • Widows peak, cleft chin, earlobe attachment: attached earlobes are recessive. Hitchhikers thumb, almond eyes, and hairy knuckles are dominant traits. • Remember that it can be homozygous or heterozygous for a dominant trait. • Huntington's disease- a deadly disease that causes brain breakdown between ages 30 and 50. This is why it is passed on, the individual does not know they carry it until it is to late.

5. Traits are not so simple • Incomplete dominance- when an individual has the middle between dominant and recessive. Neither allele is expressed, but a middle ground is. • Red flower and white flower makes a pink flower

7. Codominance of traits • Both alleles are expressed. • If a homozygote recessive and homozygote dominant mate then the offspring will be heterozygous for both traits, both are expressed • White chicken mates with black chicken and makes a black and white chicken.

9. Multiple alleles- this means that the trait (gene) is controlled by more than 2 alleles, but the cell is still diploid. • To have a certain color you have to have the correct alleles. A, b, and c are possible alleles: • A -could be red-dominant • Ab -could be green • aac -could be brown • a- could be black-recessive

10. Sex determination • There are 22 pairs of homologues • 1 pair that look different-sex chromosomes • X and y • XX is female • XY is male • Male determines gender

11. Sex linked traits- genes for a trait that are located on the X or Y chromosome • If it is Y linked, it will only affect males • X linked could be either male or female • Any recessive x link passed to a male will not be over powered by a dominant trait because there is not another x. • You write the chromosome then the trait • Eye color in flies is sex linked • XRY XRXR

13. Polygenic inheritance-many genes control the trait, the genes can be on different chromosomes. • Height of humans, skin color, height of plants are polygenic • Since a trait is on different genes there will be many alleles. • Height ABC alleles • Tall is AABBCC • Short is aabbcc • then there is a whole range in between

15. Environmental influences- This can control whether a trait is expressed or how much it is expressed • External influences • Temperature, light, chemical, and infections can all cause changes to gene expression • Changing fur color in winter, or leaf color in fall • Internal influences • Hormones, age, body structure • Males have bright feathers females do not • Men bald as they get older

16. Complex Inheritance • Sickle cell anemia (homozygous recessive)- • Caused by defective translation into protein hemoglobin-oxygen carrier • Slows down blood flow and can block blood vessels • Reduces oxygen movement through body • Causes pain • Codominance in humans- both normal and sickle cells are made • Fewer problems but they still exist

18. Multiple allele • Blood type in humans, controlled by 3 genes • IA, IB, ii • Determine the molecule on the outside of red blood cells • Must make sure to get the right blood type because unlike blood types will clump and cause death

21. Rh factor of positive and negative blood • Discovered in the Rhesus monkeys, a blood protein that is attached to the blood type • Positive means you carry the protein • Negative means you don't • Must be compatible or can cause major issues for expectant mothers

23. Sex linked human traits • Color blindness • Caused by X-linked recessive traits • Causes problems with the color receptors of the eye • Hemophilia • Blood does not clot and can cause death • X linked recessive allele carried by women • 10,000 to 1 men • 100,000,000 to 1 women • Since there is not a Y linked dominant allele the only thing it can do is be expressed as recessive

25. Polygenetic in humans • Multiple allele representation • Get a range in phenotype • Eye color • Skin color • Height

26. Genetic Technology • Selective breeding- increases the frequency of a desired allele • When humans chose what organisms breed together • Used to get the most desired traits from an animal • stronger faster horse • bigger eggs from a chicken • Faster growing corn plants • Rose color • Anything that a human could benefit from

27. Inbreeding- breeding between closely related animals • Used to get only desired traits and to rid the population of negative traits • Can bring out harmful recessive traits because of how close gene would match • Also called a pure breed • Horses and dogs are 2 good examples of pure breeds

28. Hybrid organisms- a cross between 2 organisms • Are usually bigger and healthier than the original • Cross fast growth corn with drought resistant corn • 2 pure breeds can make an even stronger organism • Use a test cross to determine the genotypes of possible unknown parents

29. Recombinant DNA Technology • Genetic engineering- taking DNA from one organism and adding it to another to get specific gene qualities • Plants that glow • Plants with qualities of 2 different plants

30. How is this done? • 1. the DNA fragment that is to be removed must be isolated using a restriction enzyme • Restriction enzyme is a bacterial protein that will cut both sides of the DNA strand at the exact same nucleotide sequence. • The cut DNA can have 2 flat ends, or ends that hang over • These will join easily with new DNA

32. To get the fragment of DNA into the new cell it must be fixed to a vector • A vector is the way a DNA sequence from one organism can be carried to another • Can be mechanical or biological • Plasmid- small ring of Bacterial DNA • This is a biological way to fix the new DNA • Viral- DNA is transported by a virus to the new cell

34. Mechanical • The use of very small tools to insert the new DNA sequence into the cell • Micropipette

35. Gene cloning- the process of making genetically identical copies of DNA • Bacteria is often used because it replicates or doubles so many times faster than other organisms • Insert a plasmid and the bacteria will replicate the plasmid DNA separate from its own • Scientists can make proteins and mutations to study how they react to certain stimuli

36. Dolly the sheep- an animal clone • Very tricky to replicate so many different genes at once • Could benefit farmers and ranchers with limitless supply of perfect plants and animals • What are some of the consequences?

37. What if you want to replicate DNA outside of the cell? • There is an app for that!!! Hahahaha • Or you could use PCR- polymerase chain reactions: http://www.youtube.com/watch?v=2KoLnIwoZKU&feature=related • Use this to replicate DNA over and over again without needing cells or getting DNA mixed up • Can make millions of copies in a day • Used for sequencing genes, investigating crimes, and studying diseases. • Only needs a small amount of DNA to make lots of copies • Why is this good?

38. Gene sequencing : http://www.youtube.com/watch?v=6ldtdWjDwes&feature=relatedhttp://www.youtube.com/watch?v=aPN8LP4YxPo&feature=related • Used to identify the sequence or correct order of DNA. Great for finding mutations. • Use PCR to make lots of copies • Then the copies are separated using gel electrophoresis: http://www.youtube.com/watch?v=QEG8dz7cbnY&feature=player_embedded#! • Like separating chlorophyll, the larger strands do not move as far as shorter strands • Then UV light can be used to see how far the bands moved

40. Electrophoresis mechanism

42. Uses of DNA technology- let bacteria make a lot of copies of certain chemicals and proteins • Indigo for blue jeans, sewage treatment options, cheese and laundry applications • Medicines like insulin for diabetics can be made from bacteria, hemophilia medications • Super plants that are infestation resistant, or do not cause allergic reactions like peanuts

43. Human genome project- map out and sequence the genes of humans • 3,000,000,000 base pairs • 35,000-40,000 genes • 46 chromosomes

44. Uses for this information • Determination of a genetic disorder • Once scientists know what a sequence should look like they can determine any abnormalities for a disorder.

45. Gene therapy- for those that have a genetic disorder • Insert normal DNA into cells to correct the disorder • Take bad cells from person, use a virus to insert the new good DNA, and then inject the cells back into the person

47. DNA fingerprinting- catch the bad guy by matching up DNA from a person and from the crime scene • Sequence it with gel electrophoresis