11.2 COMPLEX PATTERNS OF HUMAN INHERITANCE

-Inheritance of traits that do not follow the patterns described by Mendel
-The difference between sex-linked and sex-limited inheritance
-How environment can influence a trait

DEFINE: codominance
READING Q’s
-BOTH traits appear in heterozygous genotype

READING Q’s
DESCRIBE:
What effect sickle-cell anemia has on red blood cells
-changes them to sickle or C-shaped

READING Q’s
EVAULUATE
-What is the most common blood type?
-
O

READING Q’s
EVALUATE
-What allele is dominant over C ch
-
C

READING Q’s
IDENTIFY
-A person has 22 pairs of autosomes and 2 X chromosomes.
What is the person’s gender?
-FEMALE

READING Q’s
DRAW CONCLUSIONS
-Why is a recessive sex-linked trait less likely to occur in females than in males?
-males only need one recessive allele on an X chromosome to show the trait

READING Q’s
PREDICT
-Circle the genotype that represents a color-blind person
-
X b Y

READING Q’s
LIST
-An example of a polygenic trait.
-

READING Q’s
EVALUATE
-Circle the trait that shows the strongest genetic influence— highest % of trait shown in twins
-

GROUP WORK: APPLICATION NOTES
-As a group complete the application notes using your knowledge from the reading.

 VOCABULARY
REVIEW: gamete
mature sex cell with half (haploid) # of chromosomes
1-any chromosomes that are not sex chromosomes
AUTOSOMES
2-inheritance patterns-BOTH allele traits expressed in phenotype of hetero ind
CODOMINANCE
3- interaction of alleles with one allele masking effects of the other
EPISTASIS
4-inheritance pattern-phenotype is a MIX of the 2 homozygous parent traits
INCOMPLETE DOMINANCE

 VOCABULARY
5-presence of more than 2 alleles for a genetic trait
MULTIPLE ALLELES
6-inheritance pattern-trait controlled by 2 or more genes on same/different chromosomes
POLYGENIC TRAIT
7- chromosomes determine the sex of an individual, carry sex-linked characteristics
SEX CHROMOSOMES
8-traits controlled by genes located on sex chromosomes
SEX-LINKED TRAITS

 INCOMPLETE DOMINANCE
ANALYZE: the ratios of offspring
RR RR X Rr

 CODOMINANCE
DETERMINE: R=normal dominant R’=sickle cell recessive
The correct coloumn for each phenotype x x x

 CODOMINANCE
PREDICT: the results of two people who are heterozygous for sickle-cell anemia but lead normal lives have a child
RR’ x RR’
25% RR no alleles for disease
50% RR’ heterozygous/ lead normal lives
25% R’R’ homo recessive/ sickle cell disease

 MULTIPLE ALLELES
IDENTIFY: the blood group that results from each combination of genotypes

 EPISTASIS,SEX DET,DOSAGE COMP,SEX LINKED, POLYGENIC
ANALYZE: the role of each inheritance. Give example.

 EPISTASIS,SEX DET,DOSAGE COMP,SEX LINKED, POLYGENIC
REFER: to punnett square to answer questions: sex-linked
DETERMINE: gender, color vision
1-Does the father have color-blindness?  yes
2-Does the father have a recessive allele?
 yes
3-What gender is the child with color-blindness? x male  female
4-circle the offspring that is color-blind x no no

 ENVIRONMENTAL STUDIES
IDENTIFY:
Environmental influences that can affect phenotype

 TWIN STUDIES
DESCRIBE:
The use of twin studies in the study of genetics.
Scientists use twin studies to distinguish between