Human Heredity
http://www.youtube.com/watch?v=hNM
YV213xu0 – video on karyotypes
KARYOTYPE
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 7–12 days, and are easily grown in culture. Most species are selffertile 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 4:4
pattern. 4 black spores, and 4 tan spores all lined up. If crossing over does occur there is a 2:2:2:2 pattern
visible, or a 2:4:2 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.

Nondisjunction
Homologous pair fails to separate in
Meiosis I, or sister chromatids fail to
separate in Meiosis II.
Engage
Genetic Disorders
Patau Syndrome
 Edward Syndrome
 Klinfelter’s Syndrome
 Turner Syndrome
 Super Male Syndrome
 Super Female Syndrome
 Down’s Syndrome

Geneticists Wanted

WANTED: Very intelligent scientists to
help figure out what is wrong with these
children?
Karyotype printable worksheets for activity
http://www.google.com/imgres?imgurl=http://www.biologycorner.com/worksheets/karyotype/karyotypefemale.gif&imgrefurl=http://www.biologycorner.com/worksheets/karyotype/chromosomestudyteacher.html&usg=__Tm3uv0lCTIgozDBpZuNOZmzTcd8=&h=720&w=650&sz=32&hl=en&start=12&um=1&itbs=1&tbnid=tzRP25VHPwJTqM:&tbnh=140&tbnw
=126&prev=/images%3Fq%3Dkaryotype%26um%3D1%26hl%3Den%26sa%3DX%26tbs%3Disch:1
Background:
 Mr.
and Mrs. Raider are deeply
worried about their child who seems to
be developing at a slower rate. They
are concerned for the child’s 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
47, XX or XY, +13


serious eye, brain,
circulatory defects as
well as cleft palate.
1:5000 live births.
Children rarely live more
than a few months.
Patau Syndrome
Edward Syndrome

almost every organ system affected 1:10,000 live births.
Children with full Trisomy 18 generally do not live more
than a few months.
Klinefelter’s 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 XYY
- Tall male with heavy acne
- Some tendency to mental
retardation
Aggressive tendency
- Has an XXX
- Fertile
females with
normal
intelligence
Normal Female
Normal Male
Explain
Questions
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?

Disorders
Name 3-4 diseases caused by a
chromosomal abnormality.
 What most often causes this abnormal
number of chromosomes?

Terms to Know


If either of these gametes unites with another during
fertilization, the result is ________________ (any
abnormal chromosome number)
Aneuploidy has one extra chromosome (2n
A _____________cell
+1).
Trisomy
Down syndrome(trisomy
21), Klinefelters (XXY), Triple X
(XXX), Jacobs (XYY)

A ___________ cell has one missing chromosome (2n
- 1) Turners Syndrome
Monoso
my
Elaborate

Draw pedigrees from the given problems.
Engage
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
Victoria’s 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
hemophilic?
– 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 sons.
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