1. ASSESSMENT REMINDER:
If you FAIL (below 70%) an assessment, regardless of the type, you can retest (following reteach) the objective you failed for a maximum of a 70%. The retest must be done within 1 week of receiving your test back and must be done during tutorials.
If you pass an assessment that is short answer you receive the grade you got (just like last semester) and are not able to correct short answers.
If you pass an assessment that has a multiple choice portion you may CORRECT the multiple choice portion you missed for 1 point each. Corrections are made during tutorials and must be done within 1 week of receiving your test back. (Just like last semester….!)
You don’t have to schedule to retest or make corrections! Your ticket in to retest/correct is your original assessment!
6e, 6f, assessment reteach, retest, MC corrections will be the Week of February 9-13th during tutorials!!! 6f will be given back next week and grades will be in the grade book by Monday for 6f

2. Karyotypes

3. You should be able to answer the following questions by next class (based on handouts…)
How many chromosomes are present in a normal human karyotype?
What is a karyotype?
What is non-disjunction?
Which pair of chromosomes represent the sex chromosomes? How can you tell X and Y apart?
What is an aneuploidy?
Provide at least one example of an aneuploidy
What does trisomy mean? What is an example of one? How can you pick it out on a karyotype?

4. Karyotypes
Definition - A picture of chromosomes cut out and grouped together.
Typical human karyotype:
46 total chromosomes
23 total pairs
44 autosomes
2 sex chromosomes (XX or XY)
*An embryo without an X chromosome is incapable of survival

7. Is the following individual male or female?

8. Is this karyotype of a male or female? question here]

9. “Normal” Human Female Why? Because she lacks a “Y” chromosome.

11. Is the following individual male or female?

12. Is this karyotype of a male or female? question here]
Male [Option 1]
Female

13. “Normal” Human Male Why? Because he has a “Y” chromosome.

15. Non-disjunction
Non-disjunction is a failure of chromosomes to properly separate during either Stage 1 or Stage 2 of meiosis
Upon fertilization the zygote may have one too many chromosomes ( trisomy) or one too few chromosomes (monosomy)

16. Which chromosome number shows non-disjunction?

18. Monosomy X, Female Turner Syndrome
Pectus excavatum (picture)
Short stature
Webbed neck
Abnormal eye features (drooping eyelids)
Absent or retarded development of
secondary sexual characteristics
that
normally appear at puberty
Infertility
Dry eyes

19. Which chromosome number shows non-disjunction?

21. Trisomy 21 Down Syndrome, Female 47, XX, +21

22. Down Syndrome Most commonly known trisomy
1:700 births; 1 in 6 die within 1st year
Average age is 16.2 years
Common facial feature
Short stature
Stubby fingers and toes
Large tongue – makes speech difficult

23. Which chromosome number shows non-disjunction

25. Patau Syndrome (Trisomy 13)

26. Patau Syndrome (Trisomy 13)
1:15,000 births as most fetuses die before term
Of those that survive, 5% live to age 3; 45% die within the first month and 90% die within first year
Close set eyes, low set ears
Small head
Extra fingers and toes
Serious eye, brain, and circulatory defects

27. Which chromosome number shows non-disjunction?

29. XXY Klinefelter Syndrome Tall (around six feet)
Hypogonadism (small testes)
Unable to produce sperm (infertile)
Sparse facial and body hair
Gynecomastia (male breast disorder)

30. Which chromosome number shows non-disjunction

32. XYY Jacob’s Syndrome Tend to have a wiry-build Severe acne
Minor birth defects
Minor outturning of the elbows
Fertility is not affected

33. HOMEWORK, Chromosomal analysis handout (lab station 1)
It could be useful to use your karyotype flow chart to answer the questions (especially on notation)
Due next class by 9:00 (that would be Tuesday)