Mendelian
Genetics
1)Define
the following terms: true-breeding,
monohybrid experiment, Punnett square, parental
generation, F1 generation, F2 generation, locus, allele,
genotype, phenotype, dominant, recessive, homozygous, heterozygous,.
2)Briefly outline the principle of segregation and principle of independent
assortment.
3) For the two parents A1A1B1B1;
A2A2B2B2 give the frequency of the
progeny for a
a) backcross
b) F2
c) F3
4) For the two parents A1A1B2B2C1C1;
A3A3B1B1C2C2 the
frequency of the progeny for a
a) backcross
b) F2
c) F8 (Challenge)
5)You
have two true-breeding plants and you are focusing on the trait of thorn type,
one plant is homozygous for the dominant
allele of large thorns and the other is homozygous for the recessive allele of
small thorns. What will be the
segregation ratio of the F1, the F2, and the F3
generation?
6) Given
two genes, one coding for scale texture and one coding for type of exhaling,
and the alleles (rough or smooth scales, fire or smoke breathing): develop symbols for the genes and the
alleles. If you have a rough scaled,
fire-breathing plant, what are the possible genotypes? Assume that rough scales are dominant over
smooth scales and fire-breathing is dominant over smoke-breathing.
7) Construct
the F2 generation if your parental generation was made up of a rough
scaled, fire-breathing plant and a smooth-scaled, smoke-breathing plant. Assume that both parental plants were double heterozygotes. Write
out the genotypic and phenotypic ratios of the progeny.
8)Assume
that for a given breed of dog, for the trait tooth type, huge sharp teeth are
dominant over little sharp teeth and that for the trait tooth shape and size
are together determined by a single gene.
You are a dog breeder and all of your customers want dogs with huge,
sharp teeth. To maximize profits,
therefore, you want to ensure all future puppies have huge, sharp teeth. You have two litters of puppies from two
different sets of parents. One litter
all has little, sharp teeth and the other has all huge, sharp teeth. Which puppies would you use to breed and is
the litter with all little, sharp teeth of any use to you? Show the proper analysis and all possible
results that led you to your conclusions.
9)A
number of researchers repeated Mendel’s crosses in order to confirm his genetic
principles. For example, Carl Correns and Erich von Tschermak
crossed yellow and green cotyledon colored varieties of peas and
self-fertilized the subsequent F1 progeny to get F2
progeny arrays. Correns
observed 1,394 yellow and 453 green, while Tschermak
observed 3,580 yellow and 1,190 green.
Are these values consistent with the principle of segregation? Do the
test.
10)
There is a tetraploid that uses bivalent random
pairing in meiosis. What are the
possible F2 progeny of the parents (challenge)
a) A1A1A1A1; A2A2A2A2
b) A1A1A2A2;A3A3A4A4
11)
For the parents A1A2; A3A4 what is the segregation of the F2 generation?
12)
How many possible genotypes exist for a single gene diploid four allele system?
list them. How
many possible genotypes exist for a single gene diploid six allele system? List them.
How many possible genotypes exist for two genes each with four possible
alleles? List them.
13)
Define crossing over, gene conversion, recombination, chiasmata
Extrachromosomal Inheritance
14) What are mitochondria and
chloroplasts? What is their main
function and in what types of organisms are they found?
15) What is extranuclear inheritance?
Why is it referred to as extranuclear? Name and briefly describe two types of extranuclear inheritance.
Chromosome Number and
Structure
16) How many chromosomes does
a human somatic cell have in its nucleus?
Where do these chromosomes come from?
In what proportion are they found?
17) Define the following
terms: ploidy,
polyploidy, euploidy, aneuploidy,
trisomy, monosomy, nullisomy, tetrasomy,
polyploidy, autopolyploidy, and allopolyploidy.
18) Define nondisjunction and briefly outline how it occurs and
its consequences.
Mendelian Inheritance in Humans
19) In a human pedigree, describe briefly
what the following symbols represent: open
square, open circle, square connected to a circle with one line, square
connected to a circle with two lines, filled in square or circle, row of
squares and/or circles connected at the top with a horizontal line.
20) A true breeding plant
with red flowers and pointy leaves is crossed to a true breeding plant with
white flowers and round leaves. The F2
progeny are
965 red
pointy; 320 white pointy; 319 red round;
113 white round
a. . Is there a plausible Mendelian segregation for
this cross— if so justify this using Mendelian concepts
b. Test to see what happens
21. A plant with red flowers
and pointy leaves is crossed to a plant with white flowers and round
leaves. The F2 progeny are
545 red heart-shaped ; 495 white heart-shaped
a. Is there
a plausible Mendelian segregation
for this cross— if so justify this using Mendelian concepts
b. Test to see what happens
22. A plant with red flowers
and pointy leaves is crossed to a plant with white flowers and round
leaves. The F2 progeny are
485 red pointy; 515 white
pointy
a. . Is there a plausible Mendelian segregation for
this cross—if so justify this using Mendelian concepts
b. Test to see what happens
23. A plant with red flowers is crossed to a
plant with white flowers the progeny are red and white striped. A plant with yellow flowers is crossed to a plant
with a white flowered plant and the progeny are white and yellow striped. A plant with red flowers is crossed to a
plant with yellow flowers and the progeny are red. Is there a plausible Mendelian hypothesis for
this and if so test it on the following cross:
A red plant is crossed with a
yellow and white stripped plant and produces the following progeny:
57 striped red and white; 49
red; 52 yellow and white stripped; 45 yellow
24. Give the segregation ratios for the following
crosses in the F1 and F2 generations (challenge)
a.
AaBbCcDd x AaBbCcDd
b.
A1A2B1B2 x A3A4B3B4
c.
A1A2A3A4 x A1A2A3A4
25)
The flower colors of plants in a particular population may be blue, purple,
turquoise,, light blue, or white. A series of crosses between different members
of the population produced the following results (challenge)
|
Cross |
Parents |
Progeny |
|
1 |
Purple x blue |
All purple |
|
2 |
Purple x purple |
76 purple : 25 turquoise |
|
3 |
Blue x blue |
86 blue : 29 turquoise |
|
4 |
Purple x turquoise |
49 purple : 52 turquoise |
|
5 |
Purple x purple |
69 purple: 22 blue |
|
6 |
Purple x blue |
50 purple: 51 blue |
|
7 |
Purple x blue |
54 purple : 26 blue: 25 turquoise |
|
8 |
Turquoise x turquoise |
All turquoise |
|
9 |
Purple x blue |
49 purple: 25 blue: 23 light blue |
|
10 |
Light blue x light blue |
60 light blue: 29 turquoise: 31 white |
|
11 |
Turquoise x white |
All light blue |
|
12 |
White x white |
All white |
|
13 |
Purple x white |
All purple |
|
|
|
|
a) Is there
a plausible Mendelian segregation
for this cross—if so justify this using Mendelian concepts
b. Test to see what happens