Name: Karyotype Lab Block: Objective: Students will interpret karyotypes to determine the gender of individuals and whether they have chromosomal abnormalities. Problem: The genetics lab has mixed up the karyotypes of 6 patients. Use what you have learned about chromosomal disorders and the additional information provided to determine which karyotypes belong to which patients. The Patients: Patient James a 28 year old male who is trying to determine why he he can t have children. Patient Baby Jane the fetus from a 40 year-old woman. Fetal epithelial cells were obtained by amniocentesis. Patient Julia a 6 month-old girl who has weakness, pain in the abdomen and joints, swelling in the hands and feet, and sickle shaped red blood cells. Patient Justin a 45 year-old man who has started having jerky uncontrolled movements and trouble focusing his thoughts. Patient Jenny a 17 year-old girl who has never had a menstrual cycle, and has come in to find out why. Patient Johnnie a newborn baby girl who has a small head and jaw, and unusual eyes. The baby s crying sounds like a cat meowing. 1
Directions: Look at the 6 karyotypes and complete the data table by.. 1. Determining the total number of chromosomes in each karyotype 2. Record what kind of sex chromsomes each karyotype has, or other. 3. Based on the sex chromosomes, determine if the karyotype is from a male or female. 4. Record the number of any chromosome pair where there are less than or more than 2 in a pair, or if any chromosomes are broken. 5. Using you knowledge of chromosomal mutations and the information on the Tips sheet, determine what disorder would arise from the chromosomal abnormality, or if all chromosomes pairs are normal, write normal in column 6. Based on the patients symptoms and the Tips sheet, record the patient name whose characteristics best match the karyotype. Data: Karyotype # Total Number of Chromosomes Sex Chromosomes Gender (M/F) Irreguler Chromosome Pair #? Disorder Type or Normal? Patient Name 7. For which patients were the karyotypes not helpful in diagnosing their problem? - If the problem is not the result of a chromosomal mutation, what else could be the cause of the patient s problem? 2
Karyotype #1 Karyotype #2 3
Karyotype #3 Karyotype #4 4
Karyotype #5 Karyotype #6 5
Karyotype Analysis Tips Karyotype of a Normal Male There should be 46 chromosomes, with one and one chromosome in the sex pair of chromosomes Karyotype of a Normal Female There should be 46 chromosomes, with two chromosomes in the sex pair of chromosomes. Chromosomal Disorders: Down Syndrome (Trisomy 21) Nondisjunction has resulted in a karyotype with three number 21 chromosomes, for a total of 47 chromosomes. This extra chromosome is responsible for a number of symptoms: almond shaped eyes, small mouth cavity, reduced intelligence, short stature, heart defects. Chances of having a child with Down Syndrome increase as the mother s age increases. Klinefelter Syndrome (Trisomy ) Nondisjunction results in a karyotype with three sex chromosomes two s and one for a total of 47 chromosomes. The person will be a male, but will be sterile. Other symptoms include enlarged breasts, above average height, proportionally longer arms, and small testes. Cri-cu-Chat This karyotype will have a normal 46 chromosomes, but a chromosomal deletion results in a portion of chromosome number 5 to be missing. The missing genes result in the following symptoms: mental retardation, unusual facial features, digestive and circulatory problems, death by early childhood. Vocal cords are affected so the baby s cry sounds like a cat meowing. Turner Syndrome (Monosomy O) Nondisjunction results in a karyotype with only one sex chromosome--an for a total of only 45 chromosomes. The person will be female, with normal intelligence, shorter than average height, poor development of the sex organs and sterility. 6