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Human Heredity


Sordaria fimicola is often used in introductory biology and mycology labs because it ... important role in Europe's history The disease began to crop up in ... – PowerPoint PPT presentation

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Title: Human Heredity

Human Heredity
video on karyotypes
Sordaria fimicola is a species of microscopic
fungus. It is commonly found in the feces of
herbivores. Sordaria fimicola is often used in
introductory biology and mycology labs because it
is easy to grow on nutrient agar in dish
cultures. The genus Sordaria, closely related to
Neurospora and Podospora, is a member of the
large class Pyrenomycetes, or flask-fungi. The
natural habitat of the three species of Sordaria
that have been the principal subjects in genetic
studies is dung of herbivorous animals. The
species S. fimicola is common and worldwide in
distribution. The species of Sordaria are similar
morphologically, producing black perithecia
containing asci with eight dark ascospores in a
linear arrangement. These species share a number
of characteristics that are advantageous for
genetic studies. They all have a short life
cycle, usually 712 days, and are easily grown in
culture. Most species are self-fertile and each
strain is isogenic. All kinds of mutants are
easily induced and readily obtainable with
particular ascospore color mutants. These visual
mutants aid in tetrad analysis, especially in
analysis of intragenic recombination.1 The most
common form of S. fimicola is a dark brown.
Certain mutants are grey or tan. A common
experiment for an introductory biology lab class
is to cross one of the mutant types with a wild
type and observe the ratio of coloring in the
offspring. This experiment illustrates the
concepts of genetic inheritance in a haploid
organism. The eight ascospores are produced
inside an ascus. Sordaria squashes can give us
information about crossing over during meiosis.
If no crossing over then there is a 44 pattern.
4 black spores, and 4 tan spores all lined up. If
crossing over does occur there is a 2222
pattern visible, or a 242 pattern
What makes us human?
  • To analyze chromosomes, cell biologist photograph
    cells in mitosis, when the chromosomes are fully
    condensed and easy to see.
  • Biologists then cut out the chromosomes and
    group them together in pairs.
  • A picture of chromosomes arranged this way is
    known as a KARYOTYPE.

Human Karyotype
  • What Can Our Chromosomes Tell Us?
  • We can learn a lot by looking at chromosomes!
    They can tell us everything from the likelihood
    that an unborn baby will have a genetic disorder
    to whether a person will be male or female.
    Scientists often analyze chromosomes in prenatal
    testing and in diagnosing specific diseases.
    Follow the links to find out what we can learn
    from our chromosomes.

  • Making a Karyotype
  • A karyotype is an organized profile of a person's
    chromosomes. In a karyotype, chromosomes are
    arranged and numbered by size, from largest to
    smallest. This arrangement helps scientists
    quickly identify chromosomal alterations that may
    result in a genetic disorder.

  • Using Karyotypes to Predict Genetic Disorders
  • A normal human karyotype has 46 chromosomes 22
    pairs of autosomes and 2 sex chromosomes.
  • What happens when a person has something
    different, such as
  • Too many or too few chromosomes?
  • Missing pieces of chromosomes?
  • Mixed up pieces of chromosomes?

  • Too many or too few chromosomes
  • To understand how our cells might end up with too
    many or too few chromosomes, we need to know how
    the cells normally get 46 chromosomes.

Homologous pair fails to separate in Meiosis I,
or sister chromatids fail to separate in Meiosis
EngageGenetic Disorders
  • Patau Syndrome
  • Edward Syndrome
  • Klinfelters Syndrome
  • Turner Syndrome
  • Super Male Syndrome
  • Super Female Syndrome
  • Downs Syndrome

Geneticists Wanted
  • WANTED Very intelligent scientists to help
    figure out what is wrong with these children?

Karyotype printable worksheets for activity
  • Mr. and Mrs. Raider are deeply worried about
    their child who seems to be developing at a
    slower rate. They are concerned for the childs
    health just like any other parent and are asking
    you for help?

What to hand in
  • You will be given a karyotype of the child to
    determine if they have a genetic disorder and
    what kind.
  • You will then write a dialogue that could have
    taken place between the geneticist and the
    parents of the child.
  • Dialogue should be one page
  • Dialogue should include
  • -What the is the disease? / How this happened?
  • -What are the symptoms?
  • -What is the life expectancy?
  • -What they can do as parents?
  • -Is there a cure?

  • Mothers in early 20s 1 in 1,500 births
  • Mothers over 35 1 in 70 births
  • Mothers over 45 1 in 25 births

47, XX or XY, 13
  • serious eye, brain, circulatory defects as well
    as cleft palate. 15000 live births. Children
    rarely live more than a few months.
  • Patau Syndrome

Edward Syndrome
  • almost every organ system affected 110,000 live
    births. Children with full Trisomy 18 generally
    do not live more than a few months.

Klinefelters Syndrome
  • Male sex organs unusually small testes, sterile.
    Breast enlargement and other feminine body
    characteristics. Normal intelligence.

Turner Syndrome
  • the ONLY viable monosomy

  • 1 in 3,000 female births
  • Sterile females

Jacobs (XYY)
  • 1 in 1000 male births
  • Tall
  • Lower mental ability
  • Tendency for aggressiveness

Super Male and Super Female
  • - Has an XXX- Fertile females with normal
  • Has an XYY- Tall male with heavy acne- Some
    tendency to mental retardation
  • Aggressive tendency

Normal Female
Normal Male
  • How many chromosomes come from your Father?
  • How many chromosomes come from your Mother?
  • What are chromosome pairs 1-22 called?
  • What is chromosome pair 23 called?

  • Name 3-4 diseases caused by a chromosomal
  • What most often causes this abnormal number of

Terms to Know
  • If either of these gametes unites with another
    during fertilization, the result is
    ________________ (any abnormal chromosome number)
  • A _____________cell has one extra chromosome (2n
  • Down syndrome(trisomy 21), Klinefelters (XXY),
    Triple X (XXX), Jacobs (XYY)
  • A ___________ cell has one missing chromosome (2n
    - 1) Turners Syndrome

  • Draw pedigrees from the given problems.

  • Sex-Linked Recessive Hemophilia
  • The Royal Disease
  • Read the short story Alexis The Prince Who Had
    Hemophilia by-Kelley, Laureen A.Set in the
    early 1900s, this is the story of the youngest
    child of Tsar Nicholas II of Russia, last Tsar of
    Russia. The story includes how Alexis's
    hemophilia influenced the course of events in
    Russia that led to the Russian Revolution

Some History
  • Hemophilia has played an important role in
    Europe's history
  • The disease began to crop up in Great Britain's
    Queen Victorias children
  • It became known as the "Royal disease" because it
    spread to the royal families of Europe through
    Victoria's descendants

How it Spread
  • it spread through the Royal Houses of Europe as
    monarchs arranged marriages to consolidate
    political alliances.
  • We can trace the appearance of hemophilia as it
    popped up in Spain, Russia, and Prussia by
    looking at the family tree.

The Royal Family Tree
Queen Victoria's son Leopold's Family
  • His daughter, Alice of Athlone, had one
    hemophilic son (Rupert) and two other children --
    a boy and a girl -- whose status is unknown.
  • What is the chance that her other son was
  • What is the probability that her daughter was a
    carrier? hemophiliac?

The Spanish Connection
  • Now for the Spanish connection Victoria's
    youngest child, Beatrice, gave birth to one
    daughter, one normal son, and two hemophilic
  • Looking at the pedigree of the royal family,
    identify which of Beatrice's children received
    the hemophilic gene why can you make this
    conclusion? Notice that Beatrice's daughter,
    Eugenie, married King Alfonso XIII of Spain and
    had six children, one of whom was the father of
    Juan Carlos, the current King of Spain.
  • Would you predict that Juan Carlos was normal, a
    carrier, or a hemophilic?

German and Russian Influences