Download day 4- chromosomal disorders and karyotypes

Meiosis, Day 6 lecture
1.
2.
Objective: To
look at
the consequences
of chromosomal
and genetic
abnormalities
Bellwork question: Are
all mutations
bad? Give an
example
3. Hand in your
labs!
Meiosis, Day 6 lecture
1.
Objective: To
look at the consequences
of chromosomal and genetic
abnormalities
2.
Bellwork question: What will happen to you if you
copy another student’s work in college?
3. Hand in your labs!
Several of the Meiosis drawing
papers came in exactly the
same
• The right answers
should be the same.
• But how can the
wrong answers be
exactly the same
when there are so
many ways to be
wrong?
• All matching labs
have received a zero
• What do you expect
us to think about you?
About your work
ethic?
• How are we going to
fix this?
KEY CONCEPT
Mistakes in Meiosis can affect
the offspring
Chromosome Numbers
• As mentioned, “normal”
humans have 46
chromosomes, made from 23
pairs, where one is from the
mother and the other is from
the father
• If there is an error in the
production of a gamete, that a
gamete might end up with 22
or 24 chromosomes, resulting
in a zygote with 45 or 47
chromosomes.
• This is usually a deadly
condition where the zygote will
not develop, but may end up
as a miscarriage.
Nondisjunction
• Junction means to
come together
• So disjunction means
to pull apart
• So nondisjunction
means to not pull apart
when they should
• And.. We are talking
about chromosomes or
chromatids here
nondisjunction
• Having an extra chromosome is known as
a trisomy (having 3 in a pair)
• Missing a chromosome is known as a
monosomy (having only 1 of a pair)
What chromosomes determine:
• You have 22 pairs of autosomes which
determine everything about you BUT your sex
• You have 1 pair of sex chromosomes which
determine your sex (this is not the case in all
other organisms). In humans:
– XX makes you female
– XY makes you male
• A karyotype is a photo of all the chromosomes in
an individual human sorted out into their pairs.
The results?
• Monosomy= missing a chromosome
• Trisomy= an extra chromosome
Chromosomes must be caught
when cells are in metaphase,
and then sorted
Human Karyotype- how many
autosomes? How many sex
chromosomes? Male or female?
Human Karyotype- how many
autosomes? How many sex
chromosomes? Male or female?
Human Karyotype- how many
autosomes? How many sex
chromosomes? Male or female?
Autosomal trisomies•
•
•
•
•
Trisomy 8- Warkany syndrome 2
Trisomy 9- Tri 9
Trisomy 13- Patau syndrome
Trisomy 18- Edward’s.
Trisomy 21- Down’s Syndrome
Trisomy 21
Trisomy 13
• Patau syndrome was also
described in Pacific island
tribes. These reports were
thought to have been caused
by radiation from atomic bomb
tests.
• The tribes were temporarily
moved before and during the
test by an x amount of
distance. They were then put
back where they had been
taken
• All of this occurred before it
was known how long, or even
if, radiation still lingered on
after a nuclear explosion
Monosomy
• Monosomy 21 –For liveborn infants, the
only autosomal monosomy reported in
humans is monosomy 21. Signs and
symptoms of monosomy 21 are similar
to those of Down syndrome. Infants with
monosomy 21 often have numerous
birth defects and rarely survive for
longer than a few days or weeks
• Partial monosomy 11q, also known as
Jacobsen syndrome, is a rare
chromosomal disorder in which a
portion of chromosome 11 is missing or
deleted 11q monosomy
Disorders caused by abnormal Sex
Chromosomes
• Turner’s syndrome- X0- a female who has only
one copy of an X chromosome. Short, stocky,
female secondary sex char. Affected. Learning
problems
• Triplo X- Trisomy XXX- Female. Tall, mild
learning disabilties
• Klinefleter’s syndrome- XXY- a male because of
the Y chromosome. Tall, gangly, male
secondary sex char. Affected. Learning
probelms
• Extreme Klinefelter’s- XXXY-male, symptoms
more extreme than even XXY
• Super male- XYY- male, often not apparent
unless in the case of a chromosome test
Karotyping activity-save for next
class, after the test
• Do this on your ipad.
http://www.biology.arizona.edu/human_bio
/activities/karyotyping/karyotyping.html
• Homework:
1.Finish off notebook and bring back next
class
2.Test next class. What to study?
– Study guide on schedule
– Meiosis unit quizlet (pbarthol)
What to put in notebook. In this
order:
1. Bellwork
2. Connections page
3. Vocabulary (might be blank) (you should
do it though)
4. Day 1- handout
5. Day 2- notebook paper
6. Day 3 generic and chromosomal
disorders
7. Meiosis circle drawings pages