BSC 2010 Lecture Notes - Lecture 7: Thomas Hunt Morgan, Genetic Linkage, Mendelian Inheritance
Document Summary
Get access
Related Documents
Related Questions
Please show detailed work. Thanks in advance.
16. Syntenic genes can assort independently when
A) they are very close together on a chromosome.
B) they are located on different chromosomes.
C) crossing over occurs rarely between the genes.
D) they are far apart on a chromosome and crossing over occurs frequently between the genes.
E) they are far apart on a chromosome and crossing over occurs very rarely between the genes.
17. The alleles of linked genes tend to
A) segregate together more often than expected by random assortment
B) assort independently.
C) be mutated more often than unlinked genes.
D) experience a higher rate of crossing over.
E) assort independently and show a higher rate of crossing over.
18. If you know that the frequency of recombination between genes X and Y is 34% and between X and Z is 25%, can you predict the order of the three genes?
A) Yes; the order is X-Z-Y.
B) Yes; the order is X-Y-Z.
C) Yes; the order is Z-X-Y.
D) No; based on this data alone, the order could be Z-Y-X or X-Y-Z.
E) No; based on this data alone, the order could be X-Z-Y or Z-X-Y.
Question 19 - 20. You have performed the following dihybrid cross in Drosophila using the black body color (b) and vestigial wing (vg) mutations. The b+ (grey body) and vg+ (normal wing) are dominant wild type alleles. These genes are autosomal.
Female â b+ vg+/b vg à male â b vg/b vg
Progeny:
Phenotype # of Progeny
Grey body normal wing 965
Black body vestigial wing 944
Grey body vestigial wing 208
Black body normal wing 195
19. Assuming linkage between black and vestigial, the estimated recombination frequency would be:
0.17
0.09
0.82
1.00
0.50
20. What key test could you use to determine whether the observed offspring frequencies deviate from those expected by chance alone?
A) Pascal's triangle
B) The product rule
C) The Chi-square (Ï2) test
D) The law of random assortment
E) The sum rule
21. In a genome wide association study (GWAS) designed to map the gene(s) that control height you divide subjects into a group of 1000 who are all more than seven feet tall and a control group of 1000 people of average height. You find the following associations between two genetic markers and the height trait:
| Tall group | Control group | ||
| Marker 1 | Allele A | 20% | 50% |
| Allele T | 80% | 50% | |
| Marker 2 | Allele G | 15% | 15% |
| Allele C | 85% | 85% |
What is your best guess for which marker is more closely linked to a gene that influences height?
A) Marker 1
B) Marker 2
22. Two pure breeding parents produce red and white flowers. They are crossed and the F1 produces pink flowers. When the F1 are selfed to produce the F2, nine distinct classes of pigmentation are present among F2 individuals. What is your best guess of the minimum number of genes that underlie flower pigmentation in this species?
A. 2
B. 3
C. 4
D. 5
E. 6
23. In a quantitative genetic experiment you identify two genes that confer bands of color on the back of a fly. At each gene, a dominant allele causes one band of color. If flies that are heterozygous at both loci are crossed, what ratio of offspring do you expect in each phenotype (i.e., number of color bands) class? (answer options are given from lowest to highest band number)
A) 1:1:1:1:1
B) 1:2:2:2:1
C) 1:4:6:4:1
D) 4:4:4:4:4
If an organismâs diploid chromosome number is 18, how many different possible combinations of homologous chromosomes lining up during meiosis exist for the eggs or sperm produced by that organism?
| A. | 512 | |
| B. | 9 | |
| C. | 18 | |
| D. | 128 | |
| E. | 36 |
At the end of metaphase I, _______________ separate.
| A. | sister chromatids | |
| B. | germ cells | |
| C. | homologous chromosomes | |
| D. | haploid chromatids | |
| E. | centrioles |
Mendel observed that dominant traits
| A. | are seen in all of the F1 hybrid pea plants in his experiments. | |
| B. | are expressed in all plants. | |
| C. | were absent in the F1 generation of pea plants that he used in his experiments. | |
| D. | were the only traits seen in the F2 generation of pea plants in his experiments. | |
| E. | are only expressed in hybrids. |
Cytokinesis in plant cells differs from cytokinesis in animal cells because
| A. | there is no difference. | |
| B. | in plant cells, the cell plate must also divide into two parts. | |
| C. | the contractile protein, actin, is important only in plant cells. | |
| D. | plant cells have a rigid cell wall. | |
| E. | a contractile ring forms only in plant cells. |
Sickle cell anemia is an example of what type of inheritance?
| A. | complete dominance | |
| B. | incomplete dominance | |
| C. | codominance | |
| D. | multiple alleles | |
| E. | recessive dominance |
Which of the following statements is true:
| A. | The dominant allele is masked in homozygous dominant individuals. | |
| B. | With recessive genetic disorders, if both parents are carriers, the offspring will all be affected. | |
| C. | In carriers, the recessive allele causes an intermediate phenotype. | |
| D. | In recessive genetic disorders, the mother and/or father of an affected individual must also be affected. | |
| E. | With dominant genetic disorders, the mother and/or father of an affected individual must also be affected. |
Skin cancers typically develop in the
| A. | upper layers of the epidermis. | |
| B. | lower layers of the dermis. | |
| C. | subcutaneous layer. | |
| D. | lower layers of the epidermis. | |
| E. | upper layers of the dermis. |
Duchenne muscular dystrophy (MD) is inherited from an X-linked recessive allele. What is the probability that a son with Duchenne MD inherited this disease from his biological father?
| A. | 1/2 | |
| B. | 0 | |
| C. | 1/16 | |
| D. | 1/4 | |
| E. | 1/8 |
The genetic makeup of a particular trait in an individual is its
| A. | genotype. | |
| B. | heterozygosity. | |
| C. | phenotype. | |
| D. | filial. | |
| E. | dominance. |
What structure holds the sister chromatids to the spindle fibers?
| A. | chromatin | |
| B. | kinetochore | |
| C. | MPF | |
| D. | centromere | |
| E. | cyclin |
If you view a cell in which the genetic material is beginning to be visible as separate bodies, and the nucleus has disappeared from view, you may surmise that the cells is in
| A. | telophase. | |
| B. | anaphase. | |
| C. | interphase. | |
| D. | metaphase. | |
| E. | prophase. |
Gregor Mendel was successful in his analysis of the genetics of pea plants because
| A. | he examined and analyzed both the F1 and F2 generations. | |
| B. | he studied the parental plants to determine their differences. | |
| C. | he decided to only look at his results in an objective manner. | |
| D. | he studied a trait that had a strange inheritance pattern. | |
| E. | pea plants have genetics different from other organisms. |
Tall corn plants (T) are dominant to dwarf plants (tt). Solid green leaves (G) are dominant to leaves with a white tip (gg). A cross between two corn plants yielded the following phenotypes: 51 tall plants with a white tip on their leaves; 43 dwarf plants with solid leaves; 48 dwarf plants with white tips on their leaves; 45 tall plants with solid leaves. What are the genotypes of the parents that produced these plants?
| A. | None of the above | |
| B. | TtGg x Ttgg | |
| C. | ttGG x TTgg | |
| D. | TtGg x TtGg | |
| E. | TtGg x ttgg |
In humans, a gene that has been identified as causing a type of skin cancer is the
| A. | superwoman echidna. | |
| B. | mutant superman. | |
| C. | sonic hedgehog. | |
| D. | mutant mole rat. | |
| E. | superhero aardvark. |
The segregation principle states that in sexually reproducing diploid organisms the two copies of each gene
| A. | segregate from each other during meiosis. | |
| B. | must always be the same allele. | |
| C. | separate from each other during mitosis. | |
| D. | will both wind up in either the sperm or egg. | |
| E. | move together as a unit during meiosis. |
In what phases is the genetic material in the cell correctly referred to as chromatids?
| A. | metaphase and telophase | |
| B. | anaphase and metaphase | |
| C. | interphase and telophase | |
| D. | interphase and prophase | |
| E. | metaphase and prophase |
Consider two traits for an organism, determined by two genes, each of which is governed by at least two alleles. In the case of a dihybrid individual, the gametes formed will be of either the parental type or the recombinant type. Recombinant type gametes are formed because of
| A. | the principle of dihybrids. | |
| B. | multiple alleles. | |
| C. | heterozygosity. | |
| D. | incomplete dominance. | |
| E. | independent assortment. |
An allele is
| A. | an alternate form of a gene. | |
| B. | always recessive. | |
| C. | the main factor determining a trait. | |
| D. | always one of a pair. | |
| E. | the dominant form of a gene. |
After the DNA is replicated, and it condenses in prophase, two identical rods of DNA are seen. These are
| A. | spindle fibers. | |
| B. | kinetochores. | |
| C. | chromatids. | |
| D. | chromatin. | |
| E. | centromeres. |
Special cells found in the gonads that give rise to gametes upon division are called
| A. | egg cells. | |
| B. | somatic cells. | |
| C. | germ cells. | |
| D. | stem cells. | |
| E. | basal cells. |