The Human Genome Chapter 14

The Human Genome  In humans, diploid (2n) = 46  That means somatic cells have 46 chromosomes  44 autosomal chromosomes and a pair of sex chromosomes

Pedigrees  A pedigree is a diagram that traces a single trait through several generations

Individuals shaded in have attached earlobes. Is this trait dominant or recessive? RECESSIVE!! Partially shade carriers and label genotypes

Solution:

A Pedigree for a sex-linked recessive trait: Shade in known carriers and label genotypes.

Solution:

The Human Genome Chapter 14 Blood Typing and Chromosomal Genetic Disorders

Blood Typing Chart Blood Type GenotypesAntigensAntibodiesDonate to Receive from Reaction to Anti-A Reaction to Anti-B Reaction to Anti-Rh A B AB O Rh+ Rh- Use only to type blood in lab (serum reacts to antigens present)

Blood Typing Chart Blood Type GenotypesAntigensAntibodiesDonate to Receive from Reaction to Anti-A Reaction to Anti-B Reaction to Anti-Rh A I A I A, I A i B I B I B, I B i AB I A I B O ii Rh+ ++, +- dominant Rh- -- recessive Use only to type blood in lab (serum reacts to antigens present)

Blood Typing Chart Blood Type GenotypesAntigensAntibodiesDonate to Receive from Reaction to Anti-A Reaction to Anti-B Reaction to Anti-Rh A I A I A, I A i A Anti-B B I B I B, I B i B Anti-A AB I A I B AB none O ii none Anti-A Anti-B Rh+ ++, +- dominant Rh none Rh- -- recessive none *only if exposed to antigen *Rh- mothers can be exposed to the Rh antigen if the fetus is Rh+ Use only to type blood in lab (serum reacts to antigens present)

Blood Typing Chart Blood Type GenotypesAntigensAntibodiesDonate to Receive from Reaction to Anti-A Reaction to Anti-B Reaction to Anti-Rh A I A I A, I A i A Anti-B A,AB A,O B I B I B, I B i B Anti-A B,AB B,O AB I A I B AB none AB AB,A, B,O O ii none Anti-A Anti-B A,B, AB,O O Rh+ ++, +- dominant Rh none pos pos or neg Rh- -- recessive none *only if exposed to antigen pos or neg neg only *Rh- mothers can be exposed to the Rh antigen if the fetus is Rh+ Use only to type blood in lab (serum reacts to antigens present)

Blood Typing Chart Blood Type GenotypesAntigensAntibodiesDonate to Receive from Reaction to Anti-A Reaction to Anti-B Reaction to Anti-Rh A I A I A, I A i A Anti-B A,AB A,O clumps- B I B I B, I B i B Anti-A B,AB B,O -clumps AB I A I B AB none AB AB,A, B,O clumps O ii none Anti-A Anti-B A,B, AB,O O - - Rh+ ++, +- dominant Rh none pos pos or neg clumps Rh- -- recessive none *only if exposed to antigen pos or neg neg only - Use only to type blood in lab (serum reacts to antigens present) *Rh- mothers can be exposed to the Rh antigen if the fetus is Rh+

Nondisjunction  Occurs when a chromosome or chromosomes fail to separate in meiosis  Individuals end up with the wrong number of chromosomes ( 46 total)  Risk factor increases with age

Nondisjunction of Autosome  Down Syndrome caused by trisomy 21 (3 copies of chromosome #21)

Nondisjunction of Sex Chromosomes  Turner Syndrome (karyotype 45, XO): Female; sterile; sex organs do not develop at puberty  Klinefelter’s Syndrome (Karyotype 47, XXY): Male; infertility; fewer secondary sex characteristics; variations are 48, XXXY and 49, XXXXY