1. Mrs. Williams Freshman Biology Semester Two

2. Human Genetics  Humans have 23 paired chromosomes in somatic cells  Each chromosome has many genes located on it  Some genes have a simple Mendelian type of inheritance  Most traits have a complex inheritance  Polygenic traits  Multiple Alleles  Influenced by Both Genetics and Environment

3. Karyotypes  A karyotype is a diagram of chromosomes within a cell  Homologous chromosomes are paired  Autosomes (non-sex chromosomes) are arranged from largest to smallest  Largest autosome is #1: smallest autosome is #22  Sex chromosomes are last (#23)  XX in females  XY in males

5. Karyotype Info  Karyotypes can tell:  Sex of Individual  Presence of a Chromosomal Disorder  Extra or missing whole chromosomes  Large extra or missing piece of chromosome  Can’t tell:  Genetic Disorders from Small Mutations

6. Chromosomal Abnormalities  Missing or extra whole chromosomes or pieces of chromosomes  The condition is determined by which chromosome is affected  This is because each chromosome has different genes  May affect all cells  Fertilized egg had the mistake  Person may be a mosaic (some normal, some bad)  Mistake happened later in development

7. Nondisjunction  Mistake during Meiosis or Mitosis  Non-disjunction: failure of the chromosomes to separate properly  Often happens in Anaphase I when tetrads separate

8. Terms for Chromosomal Disorders  Trisomy  3 copies of one type of chromosome  Monosomy  1 copy of one type of chromosome  Only monosomy that is viable is XO

9. Specific Disorders  Down’s Syndrome (Trisomy 21)  Edwards Syndrome (Trisomy 18)  Patau Syndrome (Trisomy 13)  Turners Syndrome (XO)  Kleinfelter Syndrome (XXY)

10. Down Syndrome (Characteristics) (Characteristics)

11. Edwards Syndrome (Characteristics) (Characteristics)

12. Patau Syndrome (Characteristics) (Characteristics)

13. Turner Syndrome (Characteristics) (Characteristics)

14. Klinefelter Syndrome (Characteristics) (Characteristics)

15. Chromosomal Alterations  Chromosomal Alterations Video Chromosomal Alterations Video  Create a circle map describing chromosomal alterations while you watch the video. Be sure to include all important information!

16. Human Blood Types  Human blood types have a gene that displays multiple alleles and codominance  ABO gene has three alleles:  I A codes for an A-type ID tag on red blood cells  I B codes for a B-type ID tag on red blood cells  i codes for no ID tag on red blood cells  I A and I B alleles are codominant

17. Human Blood Types  Possible Phenotypes and Genotypes  A blood type (I A I A or I A i)  B blood type (I B I B or I B i)  AB blood type (I A I B )  O blood type (ii)

18. Inheritance of Sex  Moms give  Sons and Daughters one of their X chromosomes (random choice)  Eggs have a single X chromosome  Dads give  Daughters their X chromosome  Sons their Y chromosome  Half of the sperm carry an X  Half carry a Y

19. Patterns of Inheritance  Autosomal Dominant/Recessive  Gene for Trait is found on a autosome  Can be dominant or recessive  Sex-linked  Gene for Trait is found on a sex chromosome  Most (almost all) are found on X (many more genes than Y)  Can be dominant or recessive

20. X-Linked Traits  Moms  No “bad” X’s- 0% chance of passing on  One “bad” X- have a 50% of passing the “bad” X to their offspring  Two “bad” X’s- have a 100% chance of passing one of them on  Dads (can only have one copy)  Only pass the “bad” X to daughters; sons get the Y

21. Y-Linked Traits  Only Males can have them  Dads pass on the trait to all sons

22. X-Linked Punnett Squares  Genotypes of each parent are written as superscripts on their sex chromosomes  Ex: X H X h and X h Y  Remember males only have one copy because they only have one X  DO NOT CROSS TWO FEMALES  When analyzing data  If question asks about offspring, consider all 4  If question narrows it down to one sex, only look at the two of that sex

23. X-Linked Punnett Square

24. Recessive X-Linked Disorders  Show up more in males  Females have two X’s  Harder to inherit two “bad” X’s to show disorder  Males have only one  Easier to inherit the one copy needed for them to show the disorder

25. Exit Slip  1. Name the two things that are unique about the alleles for human blood types.  2. What are the four possible genotypes and phenotypes for human blood?  3. Draw a Punnett Square showing a cross between a female heterozygous for hemophilia and a hemophiliac male and answer the following:  A. How many male offspring have hemophilia?  B. How many female offspring have hemophilia?