Download Unit 3.4 Inheritance

Unit 3.4 Inheritance – Study Guide
Key Terms:
Dominant Allele
Homozygous
Monohybrid
Phenotype
Recessive Allele
Heterozygous
Dihybrid
Sex Linked
Codominant Alleles
Carrier
True Breeding
Locus
Test cross
Genotype
Use the Key Terms above to fill in the blanks:
1. An allele that has the same effect on the phenotype when either the homozygous or heterozygous
state. ________________________________
2. A specific form of the gene, occupying the same gene locus as other alleles of the gene.
__________________
3. The alleles possessed by an organism. _______________________________________
4. The specific position on a homologous chromosome of a gene ___________________________
5. Having two different alleles at a locus ______________________________
6. A heritable factor that controls a specific characteristic. ________________________________
7. The characteristic on an organism. _____________________________________
8. An allele that only as an effect on the phenotype when it is in the homozygous state. ________________
9. The pattern of inheritance characteristic of genes located on the sex chromosomes. ________________
10. Testing a phenotypically dominant phenotype to determine if is if heterozygous or homozygous.
________________________
11. A parent where a dominant phenotype is homozygous. ________________________________________
12. An individual that has a recessive allele of a gene that causes an adverse effect when homologous.
_________________________
13. Having two identical alleles at a gene locus. _____________________________________
14. Pairs of alleles that both affect the phenotype when present in the heterozygous state. _____________
Crosses:
15. Pure breeding long winged flies crossed with short winged flies and all the offspring are long
winged. Long winged is dominant. When these offspring are crossed with short winged flies
approximately one half of the offspring have short wings. Explain fully
16. Claire is blood group A and her husband Clive is blood group O. Celine is blood group AB and her
husband David is blood groups B. At the hospital Claire and Celine’s baby girls were born at the
same time but Clare feels the staff accidentally muddled them up. Baby Melissa given to Celine
is blood group O. Explain and demonstrate how this could be solved and determine if Celine is
correct.
17. Ethan had hemophilia but Sasha, his wife, was normal and not a carrier. Their daughter Karen
married Jacob who also had hemophilia. Determine the phenotypes of their sons and daughters.
18. A man with normal vision married a woman who also had normal vision. However two of their
five children were color blind. Explain how this could have arisen, showing which children they
were.
19. In a certain species of plant, the trait for tall is dominant (T) and the trait for short is recessive
(t). The trait for yellow seed is dominant (Y) and the trait for green seeds is recessive (y). A cross
between two plants results in 292 tall yellow plants and 103 short green plants. What is the
genotype of both of the parents? SHOW YOUR WORK.
20. How many alleles influence the phenotype in:
a. complete dominance? __________
b. incomplete dominance? __________
21. Use a Punnett Square to show the results of the following cross: Using the laws of
probabilities if RrYy x RrYy, what is the probability of producing offspring that would be
RRyy? _________________ SHOW YOUR WORK BELOW.
22. A cross was made between two fruit flies, w white-eyed female and a wild type male
(red eye).One hundred F1 offspring were produced. All males were white eyes and all
females were wild type. When these F1 flies were allowed to mate, the F2 flies were
observed and the following data was collected.
What is the most likely pattern of Inheritance?
A. Autosomal Dominance
B. Autosomal Recessive
C. Sex-linked Dominant
D. Sex-linked Recessive
P:
F1:
F2
Females
White Eye
59 WT
24 WT
26 White Eye
Males
WT
51 White Eye
23 WT
27 White eye
23. Types of Genetic Disease: Fill in the table
Type of Genetic Disease
Sex Linked
Example(s)
Huntington’s disease
Cystic Fibrosis
Sickle Cell anemia
Non-disjunction
Inheritance Pattern
AP Short Free Response Questions:
24. By convention, one map unit distance on a chromosome is the distance within which
recombination occurs 1% of the time. The rate of cross-over gives no information about the
actual distance between genes, but tells us that the order of the linked genes on a chromosome.
A. Construct a linkage map and give the order of genes on a chromosome from the following
recombination rates for genes A, B, C and D which are linked.
B. How would you calculate the recombination rate for B to C?
A to B = 72%
A to D = 13%
B to C =
C to D = 25%
AP Long Free Response Question:
1. A person with Turner’s syndrome has a genotype of XO, while a person with Klinefelter’s syndrome
has the genotype XXY. Explain how these two mutations come about.
2. Scientists understand that comparatively few genes are inherited in a simple Mendelian fashion. The
expression of most genes is altered by many things, including other genes or the environment.
choose five of the terms below and explain what they mean.
a) Pleiotropy
b) Penetrance
c) Epistasis
d) Genomic imprinting
e) Polygenic inheritance
f) Incomplete dominance
g) The effect of the environment on genes.