Modern Genetics. Genetic Patterns Each chromosome pair may contain as many as 2,000 traits....
If you can't read please download the document
Modern Genetics. Genetic Patterns Each chromosome pair may contain as many as 2,000 traits. Chromosome 1, the largest human Chromosome, contains between
Genetic Patterns Each chromosome pair may contain as many as
2,000 traits. Chromosome 1, the largest human Chromosome, contains
between 2000 and 2100 traits. These genes carry the information or
code to produce proteins. It is estimated that the 23 pairs of
human chromosomes contain 20,000 to 25,000 genes. Each of these
genes are a result of the processes of meiosis and
fertilization.
Slide 3
Five theories that resulted from Mendels work: 1.Law of
Segregation-every organism contains a pair of alleles for any
particular trait and that this Organism can pass a randomly
selected copy of one Of these alleles to its offspring.(meiosis)
The offspring then receives its own pair of alleles for that trait
by inheriting homologous chromosomes from its parents.
(recombination) 2. Law of Independent Assortment- genes located On
different chromosomes or nonhomologous Chromosomes will be
inherited independently and Randomly. This allows for diversity and
variety. Roughly 8 million combinations exist.
Slide 4
3. Gene linkage-genes for different traits that are found on
the same chromosome are linked and will be inherited together. This
is the reason why freckles and Red hair are frequently found
inherited together. 4.Sex linked-genes for traits found on the X
Chromosome will be inherited if the X chromosome Is passed to an
offspring. 5. Law of Dominance-each allele can be classified as
Dominant or recessive. If a dominant allele is in- herited it will
always be seen in the phenotype of the organism, masking the
recessive allele. For the recessive allele to be seen the organism
must inherit both recessive alleles.
Slide 5
Remember how this process works: Within the nucleus there are
homologous chromosomes-chromosomes carrying alleles for the same
trait. One allele came from the female-the Other from the male.
Because they carry the code For the same trait they are Called
homologous Chromosomes.
Slide 6
During interphase, the chromosomes replicate, making 2 of each
homologous chromosomes. The process continues through each of the
phases Of meiosis.
Slide 7
During prophase the chromosomes are very Close together. They
may exchange some Codes that are on the chromatids. This changes
The code for those traits that are linked by a Gene producing a
different combination of Alleles. Crossing over: Increases the
Diversity of Species.
Slide 8
Remember, genes are segments or specific codes of DNA. These
codes are a result of a specific pattern of nitrogen bases. If the
pattern is changed in any way the code changes, in both DNA and
RNA. C C G T A T G G C G G C A T A C C G DNA code C C G U A U G G C
- RNA code C C G T A T G G C G C C A T A G C G MUTATED DNA CODE C G
G U A U C G C MUTATED RNA CODE
Slide 9
These changes in the pattern are called mutations sometimes
good, but most of the times harmful. Mutations are harmful because
the code is changed and the function related to that code is also
changed. If the code is for protein synthesis through the RNA
Molecule, then the protein/enzymes will not form Or function
correctly. If the code is altered where there is a dominant
recessive allele and the dominant allele is not affected then the
cell will continue to function properly. Mutations in somatic cells
are not inherited. Mutations in gametes are inherited
Slide 10
Mutations can occur in several different ways: *these changes
in the pattern are results of: Viruses, chemicals, radiation ** in
most cases the body can heal these changes. 1.deletion-loss of all
or part of the code=loss of trait 2. insertion- segment is repeated
Chain becomes longer=domino effect
Slide 11
3. Cross over: genetic material from one chromatid Is exchanged
with the genetic material from its Homologous chromatid (as seen
earlier in this PPt) Few diseases result from this. Rather a
greater variety or diversity is observed.
Slide 12
4.Translocation: similar to cross over but occurs on
nonhomologous chromosomes. This means that 2 translocations occur
simultaneously because 2 nonhomologous chromosomes are involved.
This type of mutation is usually not observed (phenotypically) in a
heterozygous individual, but will affect meiosis.
Slide 13
Nondisjunction: occurs during meiosis. Chromatin Fail to
separate. One less chromatid To be inherited Normal gamete
formation One extra chromatid In gamete
Slide 14
Some disorders/diseases caused by these mutations: Deletion
Cri-du-chat, DeGeorge Syndrome Insertion Fragile X Huntingtons
disease Translocation Philadelphia gene leukemia Nondisjunction
Down Syndrome Turner Syndrome Kleinfelter Syndrome
Slide 15
Sex determination: Diploid cells contain two different Types of
chromosomes-alleles. Those chromosomes Controlling body traits are
called autosomes 22 pairs. But one pair of chromosomes control the
gender of a species, called sex chromosomes. Specifically these
alleles are found on the 23 rd pair and have the combination of XX
and XY. There is a 50/50 chance of inheriting the X and Y
Chromosome. Female = XX Mother gives X to son Male = XY Father
gives Y to son
Slide 16
Sex linked disorders/traits are those found on the X
chromosomes. Men: will be affected by the disorder if they have
Inherited the affected X :will pass the affected X to their
daughters. Women: can be carriers of the disorder if they have
Inherited only one affected X or affected if they have Inherited
both X chromosomes. :will pass the affected X to their sons.
Slide 17
Genetic Engineering: term used to describe the use of specific
techniques to move genetic material from one organism to another
organism. One small piece of DNA from a cell is removed and added
to the DNA of another cell. The new DNA that results from This
process is call recombinant DNA. This recombinant DNA will continue
to produce the polypeptide product that it was originally coded for
giving the organism a new polypeptide. This techniques improves the
functions of the Cells/organism. This can only work because the DNA
is the same for all organisms.
Slide 18
A couple of facts to remember: a.DNA is the same for all
organisms-only the pattern changes. b.Bacteria is often used as the
carrier molecule. It is called a plasmid. Think of plaster. Once
this bacteria is injected into the recipient, the recipients cells
will use the code to produce the needed protein. c.Restriction
enzymes are used to cut the DNA molecule apart.
Slide 19
Insulin, growth hormone, interferon
Slide 20
Better Crops (drought & heat resistance) Recombinant
Vaccines (ie. Hepatitis B) Prevention and cure of sickle cell
anemia Prevention and cure of cystic fibrosis Production of
clotting factors Production of insulin Production of recombinant
pharmaceuticals Plants that produce their own insecticides Some
uses of recombinant DNA
Slide 21
Cloning: an identical copy of an organism. Two organisms have
the exact DNA code. identical twins are a natural form of cloning
mitosis
Slide 22
Why clone? All DNA will be inheritable. 1.Maintain supply of
diseased lab animals for testing. 2.Grow stem cells 3.Protect
endangered species 4.Produce high quality livestock/plants for food
5.Produce drug carrying animals. Negatives: 1.Loss of diversity
2.Moral issues