1. Meiosis Mistakes Human chromosome abnormalities

2. Nondisjunction Failure of homologous chromosomes to separate during cell division Failure of homologous chromosomes to separate during cell division

3. Results 1 too many OR 1 too few chromosomes 1 too many OR 1 too few chromosomes

4. Trisomy: Trisomy: one too many one too many 47 chromosomes Monosomy: Monosomy: one too few one too few 45 chromosomes

5. How can we diagnose these abnormalities? Karyotypes Karyotypes Picture of chromosomes in a dividing (div.) cell Picture of chromosomes in a dividing (div.) cell Arranged in order by size Arranged in order by size

6. Why might this be useful? Prenatal testing Prenatal testing amniocentesis amniocentesis

7. Down’s syndrome Short stature Short stature Round face Round face Developmental Delays Developmental Delays Eyelids that Eyelids that Cover inner corner Of eyes Trisomy-21

8. Klinefelter’s syndrome Affects only males Affects only males Sterile Sterile Varying affects Varying affects Extra X Chromosome

9. Edward’s syndrome Growth deficiency Growth deficiency Feeding difficulties Feeding difficulties Breathing difficulties Breathing difficulties Developmental delays Developmental delays Underdevelopped organs Underdevelopped organs Small head Small head Low-set, malformed ears Low-set, malformed ears Cleft lip/palate Cleft lip/palate Overlapped, flexed fingers Overlapped, flexed fingers Trisomy 18 Trisomy 18

10. Patau syndrome heart defects heart defects sloping forehead, sloping forehead, small or missing eyes, small or missing eyes, low set ears, low set ears, cleft palate cleft palate extra fingers and toes extra fingers and toes Developmental delays Developmental delays Trisomy-13 Trisomy-13

11. Who determines the sex of the child? Who determines the sex of the child?

12. THE FATHER! THE FATHER!