Genetics Sample Test 1
(1/8)^3
A dihybrid (AaBb) lab mouse is testcrossed. What is the probability that the first three offspring are dihybrid females?
three
A dihybrid plant was crossed; the F2 generation consisted of: 860 tall plants with purple flowers; 285 dwarf, purple plants; 340 tall, pink plants; and 115 dwarf, pink plants. The data remind you of a 9:3:3:1 ratio. How many degrees of freedom apply to the test of this hypothesis?
reject your hypothesis
A dihybrid plant was crossed; the F2 generation consisted of: 860 tall plants with purple flowers; 285 dwarf, purple plants; 340 tall, pink plants; and 115 dwarf, pink plants. The data remind you of a 9:3:3:1 ratio. The critical chi-square for two degrees of freedom (d.f.) = 5.991; three d.f. = 7.815; four d.f. = 9.488; nine d.f. = 16.919. Therefore you should...
10.11
A dihybrid plant was crossed; the F2 generation consisted of: 860 tall plants with purple flowers; 285 dwarf, purple plants; 340 tall, pink plants; and 115 dwarf, pink plants. The data remind you of a 9:3:3:1 ratio. What is the chi-square value in the test of this hypothesis?
10
A plant of genotype Ccdd is crossed to ccDD and an F1 test crossed to ccdd. If the genes are linked, and 20cM apart, the percentage of ccdd recombinants will be...
27/64
A trihybrid plant, exhibiting independent assortment at all three loci, is self-fertilized. What is the probability that an offspring will have the dominant phenotype at all three loci?
more than one
A woman of blood type O has a type O child. A man of which blood type could have been the father?
she should not blame the accident because she carried the hemophilia allele
A woman whose husband worked at the Chernobyl nuclear reactor gives birth to a hemophilic son,...
female, male
An organism is diploid with an XXY sex chromosome complement. It would be a _________ fly, _________ human being.
male, male
An organism is diploid with an XYY sex chromosome complement. It would be a _________ fly, _________ human being.
1:2:1:2:4:2:1:2:1
Assuming codominance for both genes, what is the phenotypic ratio of the offspring of the cross AaBb x AaBb?
1:1:1:1
Assuming complete dominance, what is the phenotypic ratio of the offspring of the cross AaBb x aabb?
3:6:3:1:2:1
Corn has a color gene and a height gene with the following phenotypes: CC and Cc, purple; cc, white; TT, tall; Tt medium; tt, dwarf. If a dihybrid is self-fertilized, what is the resulting phenotypic ratio?
1:1:1:1
Full pod shape (F) is dominant to constricted pod shape (f), and yellow pod color (Y) is dominant to green pod color (y) in pea plants. A pure-breeding green plant with full pods is crossed with a pure-breeding yellow plant with constricted pods. The offspring are then test crossed. What is the expected phenotypic ratio of the offspring?
ffYY
Full pod shape (F) is dominant to constricted pod shape (f), and yellow pod color (Y) is dominant to green pod color (y) in pea plants. What is the genotype of the yellow plant with a constricted pod?
10
Genes a and b are 10 map units apart, b and c are 20 map units apart, and a and c are 30 map units apart. If a triple heterozygote is testcrossed, among 1,000 progeny, how many are expected to result from double crossovers if interference = 0.5?
20
Genes a and b are 10 map units apart, b and c are 20 map units apart, and a and c are 30 map units apart. If a triple heterozygote is testcrossed, among 1,000 progeny, how many are expected to result from double crossovers if there is no interference?
male
If a fruit fly is a normal diploid for its autosomes but has one X and no Y chromosome, what sex is it?
zero
How many Barr bodies are found in the nuclei of an XYY human male?
one
How many Barr bodies would a cell from an XXYY human being have?
23
How many chromosomes (as opposed to chromatids) are there in metaphase II of meiosis in human beings?
three
How many different phenotypes can be expressed in a character controlled solely by a one gene, two-allele system, in which the alleles are codominant?
23
How many tetrads are there in metaphase I of meiosis in human beings?
X-linked dominant
If the father and all his daughters but none of his sons have a genetic disease, how is the trait most likely inherited?
12.5
In Drosophilia, the two genes "w" and "sn" are X-linked and 25 map units apart. A female fly of genotype w+sn+/w sn is crossed to a male from a wild-type line. What percentage of male progeny will be w+sn?
16
In a four-point test cross the number of phenotypic classes of progeny expected is...
0.001296
In maize, two plants that are heterozygous for the recessive alleles a and b are crossed, what frequency of double-mutant progeny will appear if a and b are 7.2 map units apart, and both parents carry a and b in trans (configuration)?
there was no known physical basis for Mendel's "gene" concept at the time
Mendel's work on the rules of inherited traits was not appreciated until it was rediscovered in 1900 because...
anaphase of meiosis I
Segregation and independent assortment (as defined by Mendel) occur during...
dihybrid cross
The cross AaBb x AaBb is called a...
testcross
The cross AaBb x aabb is called a...
28
The following recessive alleles are found in corn: g, glossy leaf and r, red aleurone. A hybrid of unknown origin is testcrossed, with the following 1,000 progeny resulting: red, 127; glossy, 153; wild-type, 352; and glossy + red, 368. What is your best estimate of the map distance between glossy and red, in map units?
glossy, red
The following recessive alleles are found in corn: g, glossy leaf and r, red aleurone. A hybrid of unknown origin is testcrossed, with the following 1,000 progeny resulting: red, 127; glossy, 153; wild-type, 352; and glossy + red, 368. Which of the following could have been a parent of the dihybrid, assuming the parents were homozygous?
interphase
The stage between mitosis in eukaryotic cells is called...
(1/2)^5
What is the probability that a gamete formed in a female in a Drosophilia species with 2n =10 will have only paternal centromeres?
A, B , O
Which of the following could be the blood type of the father of a type A child with an AB mother?