http:www.ornl.govscitechresourcesHuman_Genomeposterschromosomechooser.shtml

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• http//www.ornl.gov/sci/techresources/Human_Genome
  /posters/chromosome/chooser.shtml

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Genetics
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Gregor Mendel

• Genetics is the study of traits and their
  inheritance.
• A 19th century monk, is recognized as The Father
  of Modern Genetics.
• He studied the traits of pea plants while working
  on the monastery garden from 1856-1863, by cross
  pollinating and self pollinating.
• Grew over 10,000 pea plants. Wasnt until 1900
  that his results were understood.

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• He crossed plants with specific characteristics
  such as seed shape, seed colour, pod shape and
  flower position (and many others)
• By looking at one trait at a time, and using the
  rules of probability, Mendel recognized
  distinctive patterns of inheritance.

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Mendels Laws

• Law of Segregation
• Each inherited trait is defined by a gene pair.
• Parental genes are randomly separated to the sex
  cells so that sex cells only contain 1 genetic
  marker of information (allele) of a trait from
  each parent.

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• Law of Independent Assortment
• Specific information for traits (genes) are
  sorted separately from one another so that the
  inheritance of one trait is not dependent on the
  inheritance of another.
• Does having a baby boy influence the sex of the
  next child?

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• 3. The Law of Dominance
• An organism with different forms of a trait will
  express the form that is dominant.

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Independent Events in Genetics

• A random chance event (flipping a coin).
• The probability of 1 event happening does not
  influence the next event.
• In order to predict the outcomes, one must first
  understand all of the possible outcomes.
• Probability predicts the chances that certain
  events will or will not occur.

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FYI - Genetics and Cancer

• It is estimated that the minority of cancer cases
  are inherited (5-10)
• There are two types of genetic changes or
  mutations
• those that are passed down from generation to
  generation (germline mutations)
• those that happen during the lifetime of a person
  and are not passed on to the next generation
  (somatic mutations).
• The most common cancers that may, in some cases,
  be due to an inherited mutation are breast,
  ovarian, bowel and womb (endometrial) cancer.
  Genetic tests can identify some of the genes
  responsible for these cancers.

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Mendels Plant Crosses

• Mendel crossed pure-breeding plants (parental
  P) with round seeds and crossed them with
  pure-breeding plants that (P) had wrinkled seeds.
• All the first generation plants had round seeds
  (F1)
• Mendel crossed an F1 with another F1, which gave
  rise to the second generation (F2).
• The F2 generation were ¾ round seeds and ¼
  wrinkled seeds.

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• Mendel then called round seeds in the F1 plants
  the dominant form of the trait, and called the
  wrinkled seeds the recessive form (the trait
  being seed shape).

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• Mendel proposed that each pure-breeding plant had
  2 identical copies of a factor for a particular
  trait.
• He thought that only 1 of these traits went into
  each sperm or egg cell when gametes are formed.
• Mendel called this separation of the factors,
  the principle of segregation.

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• We know now that these factors are called genes
  physical unit of heredity in the DNA.
• An allele is a possible form of a gene.

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FYI - Genes and Paralysis

• Mutations in the SCN4A gene cause hyperkalemic
  periodic paralysis.
• The SCN4A gene provides instructions for making a
  protein that plays an essential role in muscles
  used for movement (skeletal muscles). For the
  body to move normally, these muscles must tense
  (contract) and relax in a coordinated way. Muscle
  contractions are triggered by the flow of certain
  positively charged atoms (ions), including
  sodium, into muscle cells. The SCN4A protein
  forms channels that control the flow of sodium
  ions into these cells.
• Mutations in the SCN4A gene alter the usual
  structure and function of sodium channels. The
  altered channels cannot properly regulate the
  flow of sodium ions into muscle cells, which
  reduces the ability of skeletal muscles to
  contract. Because muscle contraction is needed
  for movement, a disruption in normal ion
  transport leads to episodes of muscle weakness or
  paralysis.

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FYI - Genes and Dwarfism

• Mutations in the FGFR3 gene cause achondroplasia.
• The FGFR3 gene provides instructions for making a
  protein that is involved in the development and
  maintenance of bone and brain tissue. This
  protein limits the formation of bone from
  cartilage (a process called ossification),
  particularly in the long bones. Two specific
  mutations in the FGFR3 gene are responsible for
  almost all cases of achondroplasia. Researchers
  believe that these mutations cause the protein to
  be overly active, which interferes with skeletal
  development and leads to the disturbances in bone
  growth seen with this disorder.
• The average height of an adult male with
  achondroplasia is 131 centimeters (4 feet, 4
  inches), and the average height for adult females
  is 124 centimeters (4 feet, 1 inch).
  Characteristic features of achondroplasia include
  an average-size trunk, short arms and legs with
  particularly short upper arms and thighs, limited
  range of motion at the elbows, and an enlarged
  head (macrocephaly) with a prominent forehead.
  Fingers are typically short and the ring finger
  and middle finger may diverge, giving the hand a
  three-pronged (trident) appearance. People with
  achondroplasia are generally of normal
  intelligence.

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FYI - Genes and skin colour

• It certainly seems possible for two white people
  to have a black baby even if the baby's
  grandparents appear white as well. Even though
  the genetics behind all of this are really poorly
  understood, there are lots of stories where white
  parents have black babies. In fact, one such
  story may become a movie.

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Genes and Diseases

• http//www.ncbi.nlm.nih.gov/books/bv.fcgi?callbv.
  View..ShowSectionridgnd.preface.91

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Genetics Terminology

• The allele for the dominant form of a trait is
  represented by a capital letter.
• The recessive allele for the same trait is
  represented by the same letter, but in lower
  case.

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Dominants and Recessives

• http//www.blinn.edu/socialscience/LDThomas/feldma
  n/handouts/0203hand.htm

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Common terms in genetics

• Genotype the alleles that form the genetic
  makeup ie. the letters
• Phenotype its physical appearance
• Homozygous or pure-breeding, contains either
  only the dominant or only the recessive alleles.
  ie. RR or rr
• Heterozygous contains both the domiant and the
  recessive alleles. ie. Rr

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Punnett Squares Monohybrid Cross

• Investigates only 1 trait at a time
• Punnett squares are diagrams that help predict
  all the possible outcomes as well as the
  probabilities of the cross.

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Questions

• 1. Cross RR with Rr (P) and find the F1.
  Identify F1 as purebred, homozygous dominant,
  homozygous recessive and heterozygous.

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• 2. Cross two heterozygous plants where straight
  is dominant and curled leaves are recessive.
  Calculate the probability of having the phenotype
  of curled leaves.

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• 3. A cross between a small plant and a large
  plant produced F1 that were all small. What
  where the parents genotype?

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• 4. A cross between a green seeded plant and a
  green seeded plant produced the following results
  in the F1. 76 green and 24 brown seeds. What
  were the genotypes of the parents what percentage
  of the F1 are expected to be pure-bred?

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Incomplete Dominance

• In some cases, the heterozygous condition results
  in a mix between the dominant and the recessive
  traits.
• Occurs when there appears to be 3 phenotypes in
  the offspring

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Question

• When a purebred silver-tipped fox is crossed with
  a pure-bred black-tipped fox, all the F1 are gray
  tipped.
• What are the probabilities of all the genotypes
  and phenotypes when two F1s are crossed?

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FYI - Eye colour

• In humans three genes involved in eye color are
  known. They explain typical patterns of
  inheritance of brown, green, and blue eye colors.
  However, they don't explain everything. Grey eye
  color, Hazel eye color, and multiple shades of
  blue, brown, green, and grey are not explained.
  The molecular basis of these genes is not known.
  What proteins they produce and how these proteins
  produce eye color is not known. Eye color at
  birth is often blue, and later turns to a darker
  color. Why eye color can change over time is not
  known. An additional gene for green is also
  postulated, and there are reports of blue eyed
  parents producing brown eyed children (which the
  three known genes can't easily explain
  mutations, modifier genes that supress brown,
  and additional brown genes are all potential
  explanations).
• Little or no pigment gives blue eyes, some
  pigment results in green, and lots of pigment
  gives brown eyes. The amount of pigment is
  determined by at least two genes in special cells
  called melanocytes.
• A common form of heterochromia is one blue eye
  and one different colored eye. One way to end up
  with a blue eye is if part of one eye is missing
  melanocytes. Another way is if an eye color gene
  only works in one eye.

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Assignment

• Variations on a human face

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Handout

• Genetics Problems Sheet 1

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Punnett Squares - Dihybrid Crosses

• Looks at 2 different traits at one time.
• Need to predict the allele combination of each
  parent.
• This prediction is done similar to the FOIL
  method.

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Question

• What is the allele combination of a homozygous
  dominant? Recessive? Heterozygous?

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• 2. What is the punnett square of a cross between
  2 heterozygous plants for both traits? Use the
  letters a and b.

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• 3. What is the genotype of the cross between
  AaBB and AaBB?

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• 4.A brown round plant was crossed with itself.
  The F1 produced the following results. 9 brown
  and round, 3 brown and wrinkled, 3 red and round
  and 1 red and wrinkled. What are the genotypes
  of the P?

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• 5. A brown wrinkled plant was crossed with an
  unknown genotype of a plant. The F1 had the
  following results. 1111. What were the
  genotypes of the Ps?

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• 6. Helen found that the heterozygous condition
  TtRr gave an intermediate stage called medium
  height and roundish. If T is tall and t is
  short, and R is round and r is wrinkled, what are
  the genotypes and phenotypes of the following
  cross?
• TtRr x TTrr

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Handout

• Genetics Problems Sheet 2

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Lab

• Human Genetics
• Single-factor Inheritance

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Phenotypic Ratio

• The purpose of the ratio is to show an
  inheritance pattern.
• What is the phenotypic ratio for the following?

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Test Cross

• The purpose of a Test Cross is to determine if
  any of the parental genotypes are heterozygous.
• To make a test cross, one parent must be
  homozygous recessive for all traits. ie. aabb
• If an unknown parental genotype is crossed with a
  test cross, the occurrence of any recessive
  phenotypes will indicate that the parent was
  heterozygous.

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Problem

• Set up a test cross with a parent that is
  heterozygous for round (dominant) seeds and
  homozygous for green leaves (dominant).

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Sex Linked Traits

• There is one chromosomal pair that is responsible
  for the sex of the child.
• Male is XY
• Female is XX
• There are some traits that only males can get
  because of the smaller Y chromosome.
• Colourblindness, hemophilia are examples

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• Female
• XNXN - regular
• XNXn regular (carrier)
• XnXn shows recessive
• Male
• XNY - regular
• XnY shows recessive

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Questions

• A sex linked recessive allele produces a
  red-green colourblindness. A normal woman whose
  father was colourblind, marries a colourblind
  man. What are the genotypes? Make a pedigree.

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• Handout Pedigrees and Sex-Linked (Ch. 7 and 8)

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• http//www.biology.arizona.edu/mendelian_genetics/
  problem_sets/sex_linked_inheritance/sex_linked_inh
  eritance.html

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Multiple Alleles

• A number of human traits are the result of more
  than 2 types of alleles. Such traits are said to
  have multiple alleles for that trait.
• Blood type is an example of a common multiple
  allele trait. There are 3 different alleles for
  blood type, (A, B, O). A is dominant to O. B is
  also dominant to O. A and B are both co-dominant.
• This discovery was led by the question why
  transfusions were healing some, but killing others

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Rhesus Factor

• The term Rhesus (Rh) blood group system refers to
  the five main Rhesus antigens (C, c, D, E and e)
  as well as other less frequent Rhesus antigens.
• The terms Rhesus factor and Rh factor are
  equivalent and refer to the Rh D antigen only.
• There may be prenatal danger to the fetus when a
  pregnant woman is RhD-negative and the biological
  father is RhD-positive.

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• http//www.biology.arizona.edu/mendelian_genetics/
  problem_sets/monohybrid_cross/11q.html

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• What are the possible blood types of the
  following?
• A mother and A father
• A mother and O father
• B mother and AB father

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Nucleic Acids

• Deoxyribonucleic Acid
• Ribonucleic Acid

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What are Nucleotides?

• The building blocks of DNA and RNA.
• Consist of
• A phosphate
• A 5-C sugar (ribose or deoxyribose)
• A Nitrogen Base

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Differences between DNA and RNA

• DNA
• Doubled stranded
• Adenine Thymine
• Guanine Cytosine
• Stores all information
• Determines genetic characteristics

• RNA
• Single stranded
• Adenine Uracil
• Guanine Cytosine
• Needed for protein synthesis
• 3 kinds
• rRNA (ribosomal)
• mRNA (messenger)
• tRNA (transfer)

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Replication of DNA

• http//207.207.4.198/pub/flash/24/menu.swf
• What are the purine and pyrimidine bases?
• Where does hydrogen bonds occur? What are
  hydrogen bonds?
• What is complementary in the DNA strands?
• What is the purpose of replication?
• Why is DNA replication refered to as
  semi-conservative?

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• What is the first step for replication?
• What is the leading strand?
• What is the purpose of the enzyme helicase?
• What do Single-Strand Binding Proteins do?
• What is a replication bubble?
• What does DNA polymerase do?
• What does RNA primase do?
• What is RNA primer?
• What replaces the RNA primer with DNA?
• Where does the energy come from to polymerize the
  new DNA strand?

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• What is polymerization?
• What is the lagging strand?
• Why is it said that the lagging strand is built
  discontinuously?
• What is the purpose of ligase on the lagging
  strand?

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Protein Synthesis

• http//www.wisc-online.com/objects/index_tj.asp?ob
  jIDAP1302
• The cell gets a message to make a protein.
• A portion of the DNA unwinds
• mRNA is produced from base-pairing with the
  exposed DNA. This is called transcription, in
  which the message in DNA is made into RNA

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• Gyanine matches with cytosine
• Adenine matches with uracil
• The mRNA leaves via the nuclear pores
• A mRNA binds with the ribosome
• The message is read 3 base pairs at a time
  (called a codon)

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• An enzyme activates the correct AA
• A tRNA attaches to the correct AA and the tRNA
  base-pairs with the codon (called an anticodon).
  This is called translation as the information in
  RNA is used to assemble the AA sequence of a
  protein)
• The ribosome continues to read the codons and the
  AA are attached with a peptide bond using ATP as
  the energy source

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• A polypeptide chain is produced
• Introns segment of DNA that does not code for
  AA sequence of a protein.
• Exons segment of DNA that codes for AA sequence
  of a protein.

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Mitosis

• The billions of cells that make up your body are
  descendants of the original cell and products of
  countless cell divisions.
• Each time replication and cell division occurs,
  the daughter cells (the new cells) receive
  identical material from the mother cell.
• A diploid cell (2n) makes another diploid cell.

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Life Span of Different Human Body Cells
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The Cell Cycle

• Replication and division of the nuclear material
  and cytoplasmic material is the cell cycle.
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase

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Interphase

• Most of the cell life is in this non-dividing
  phase. Chromosomes appear as chromatin as they
  are not extended.
• Parts of Interphase stage
• G1 in which newly divided cells grow in size
• S the number of chromosomes double
• G2 where enzymes and cellular materials are
  made for the dividing stages

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Prophase

• DNA condenses.
• Centrioles move towards opposites ends (poles)
• Microtubules form from the centrioles
• Nuclear membrane and nucleolus breaks down.

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Metaphase

• Microtubules attach to sister chromatids to form
  a spindle apparatus.
• All chromosomes line up in the middle (equator)
  of the cell.

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Anaphase

• Centromere of each sister chromatids splits and
  one chromatid from each moves to centrioles at
  the poles of the cell.

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Telophase

• 2 new cells begin to form with either cell
  pinching (cleaving) in animals or having a cell
  plate in plants forming.
• Cytokinesis occurs
• Chromosomes become less condensed and turn to
  chromatin.
• New nuclear membranes form as well as the
  nucleolus reforms

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Mitosis Lab

• Locate the meristematic zone or growth zone which
  is near the end of the root.
• Focus in on low power, then to medium and then to
  high.
• Count the number of cells found in each stage and
  place the data in a chart.
• Determine the of time each cell will spend in
  each stage. Divide the number of each cell by
  the total number of cells and then multiply by
  100,

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• Line graph the data collected

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Meiosis

• Gametes are haploid, with a single set of
  chromosomes.
• The new individual is called a zygote, with two
  sets of chromosomes (diploid).
• Meiosis is a two-stage process to convert a
  diploid cell to a haploid gamete, and cause a
  change in the genetic information to increase
  diversity in the offspring.

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http//www.cellsalive.com/meiosis.htm
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Meiosis I

• Interphase I
• G1 in which newly divided cells grow in size
• S the number of chromosomes double
• G2 where enzymes and cellular materials are
  made for the dividing stages

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• Prophase I
• Chromosomes align into homologous pairs (remember
  you have 23 pairs of chromosomes, 1 pair is the
  sex chromosomes and 22 pairs are autosomes).
• These pairings are not exact copies, but they
  code for the same genes (remember dominant and
  recessive).
• Nucleolus disappears, nuclear membrane
  disappears, centrioles migrate to opposite poles
  and spindle fibers form

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• Synapsis occurs linking the pairs of homologous
  chromosomes into a tetrad.
• Sometimes a process known as crossing-over occurs
  to exchange genetic material between non-sister
  chromatids.

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• The alleles on this tetrad
• A B C D E F G
• A B C D E F G
• a b c d e f g
• a b c d e f g
• will produce the following chromosomes if there
  is a crossing-over event between the 2nd and 3rd
  chromosomes from the top
• A B C D E F G
• A B c d e f g
• a b C D E F G
• a b c d e f g

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The point where the 2 non-sister chromatids
interwine is called a chiasma, and the result is
known as recombinant chromatids.
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• Metaphase I
• The spindle apparatus forms from the centrioles.
• Tetrads align in the middle.

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• Anaphase I
• Homologous chromosomes are pulled to opposite
  poles

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• Telophase I
• Nuclear membrane reforms
• Cytokinesis occurs to split the cytoplasm and
  contents for the 2 cells.

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Interphase (II)

• Interkinesis (aka Interphase II)
• A resting stage occurs in which no replication
  occurs.

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Prophase II

• Centrioles move towards the opposite poles.
• Nuclear membrane disappears.
• Dyads (1/2 of the tetrad) consist of sister
  chromatids are connected by a centromere.

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• Metaphase II
• The dyads line up in the middle.

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• Anaphase II
• Each sister chromatid is pulled to opposite poles.

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• Telophase II
• The chromatids reach the poles of the cell.
• A nuclear membrane reforms.
• Cytokinesis occurs.
• Cell cleaving (pinching) occurs to produce 4
  haploid cells

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Karyotyping

• Refers to a photograph of the chromosomes of a
  cell at the time of when each chromosome still
  consists of two sister chromatids attached to
  each other at their centromere.

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Do Identical Twins have the same fingerprints?

• Another physical difference between identical
  twins is their fingerprints. The fingerprints of
  identical twins do look more similar than the
  fingerprints of non-twins. This is because your
  fingerprints are partially controlled by your
  genes.
• But they are not exactly the same. They have
  differences that a fingerprint expert can use to
  tell them apart. This is because environmental
  differences like how the hand of the fetus
  touches the amniotic sac also affects
  fingerprints.

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http//www.thetech.org/genetics/
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Nondisjunction

• Means literally not coming apart
• Normally each chromosome separates when producing
  gametes, sometimes more or less chromosomes are
  sent into the gametes.

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Karyotype of a boy with Down Syndrome
Patau syndrome (trisomy 13) serious eye, brain,
circulatory defects as well as cleft palate.
15000 live births. Children rarely live more
than a few months.
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Edwards syndrome (trisomy 18) almost every
organ system affected 110,000 live births.
Children with full Trisomy 18 generally do not
live more than a few months.
Klinefelter syndrome (XXY males). Male sex
organs unusually small testes, sterile. Breast
enlargement and other feminine body
characteristics. Normal intelligence.
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XYY males Individuals are somewhat taller than
average and often have below normal intelligence.
At one time (1970s), it was thought that these
men were likely to be criminally aggressive, but
this hypothesis did NOT stand up to testing and
has been disproven over time.
XXX female. 11000 live births - healthy and
fertile - usually cannot be distinguished from
normal female except by karyotype.
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Turners syndrome (X) 15000 live births the
only viable monosomy in humans - women with
Turner's have only 45 chromosomes!!! XO
individuals are genetically female, however, they
do not mature sexually during puberty and are
sterile. Short stature and normal intelligence.
(98 of these fetuses die before birth)
Cri du chat A specific deletion of a small
portion of chromosome 5 these children have
severe mental retardation, a small head with
unusual facial features, and a cry that sounds
like a distressed cat.
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Fragile X the most common form of mental
retardation. The X chromosome of some people is
unusually fragile at one tip - seen "hanging by a
thread" under a microscope. Most people have 29
"repeats" at this end of their X-chromosome,
those with Fragile X have over 700 repeats due to
duplications. Affects 11500 males, 12500
females.
XXXXY Syndrome is a very rare sex chromosome
abnormality with an approximate incidence of 1 in
85,000 male births.  Sometimes, 49, XXXXY
Syndrome is referred to as a variant of
Klinefelter Syndrome.
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Genetic Disorders

• What are the following?
• Page 550 Sickle cell anemia
• Page 551 PKU, Tay-Sachs
• Page 551 Cystic Fibrosis
• Page 551 Huntingtons Disease

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Huntingtons Disease

• http//www.accessexcellence.org/AE/AEC/AEF/1995/ma
  rtin_testing.php

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More About Genes

• Page 538 environmental factors such as
  temperature on rabbit fur.
• Page 521- Gene Linkage genes not assorting
  independently
• Page 539 Oncogenes genes that cause some
  kinds of cancer.

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Genetic Engineering

• pg.557-561

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Cloning

• http//atheism.about.com/library/chronologies/blch
  ron_sci_cloning.htm

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Cloning a Dinosaur?

• http//www.time.com/time/magazine/article/0,9171,9
  96609,00.html