Concept explainers
A small population of deer living on an isolated island are separated for many generations from a mainland deer population. The populations retain the same number of chromosomes and but hybrids are infertile. One chromosome (shown here) has a different banding pattern in the island population than in the mainland population.
Describe how the banding pattern of the island population chromosome most likely evolved from the main-land chromosome. What term or terms describe the difference between these chromosomes?
Draw the synapsis of these homologs during prophase I in hybrids produced from the cross of mainland with island deer.
In a
Suppose that
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Suppose researchers studied the first chromosome of a new species and mapped three genes of interest, indicated as a, b, and c. A three‑factor cross was performed and the number of gametes formed from the F2 generation was recorded in a table. Note that the order of genes in the table is arbitrary. Calculate the recombination frequencies for each given gene pair in map units. ?+ ?+ ?+ ? ? ? ? ?+ ?+ ?+ ? ? ? ?+ ? ?+ ? ?+ ? ? ?+ ?+ ?+ ? 173 176 35 33 11 10 3 1 After completing the gene mapping, the researchers treated individuals to induce inversions in the chromosomes. After treatment, another three‑factor cross was performed and the number of gametes formed from the F2 generation was recorded in a second table. Note that the order of genes in the table is arbitrary. ?+ ?+ ?+ ? ? ? ? ?+ ?+ ?+ ? ? ? ?+ ? ?+ ? ?+ ? ? ?+ ?+ ?+ ? 188 185 24 26 1 0 49 46 Calculate the recombination frequencies for each given gene pair in map units.arrow_forwardIn an electrophoretic gel across which is applied a powerful electrical alternating pulsed field, the DNA of the haploid fungus Neurospora crassa (n = 7) moves slowly but eventually forms seven bands, which represent DNA fractions that are of different sizes and hence have moved at different speeds. These bands are presumed to be the seven chromosomes. How would you show which band corresponds to which chromosome?arrow_forwardConsider the example of the fusion of chromosome 21 and 14. By itself, this fusion does not cause any phenotypic differences in the carrier individuals. However, the children of carriers have a very high rate of down syndrome, as well as low fertility. Explain why this is? Be specific about what differences in chromosome number may occur in offspring, and how this occurs. Please answer asap and in short and content should not be palgarised please answer asap Consider the example of the fusion of chromosome 21 and 14. By itself, this fusion does not cause any phenotypic differences in the carrier individuals. However, the children of carriers have a very high rate of down syndrome, as well as low fertility. Explain why this is? Be specific about what differences in chromosome number may occur in offspring, and how this occurs.arrow_forward
- A cytogeneticist has collected tissue samples from members of acertain butterfly species. Some of the butterflies were located inCanada, and others were found in Mexico. Through karyotyping,the cytogeneticist discovered that chromosome 5 of the Canadianbutterflies had a large inversion compared with chromosome 5 ofthe Mexican butterflies. The Canadian butterflies were inversionhomozygotes, whereas the Mexican butterflies had two normalcopies of chromosome 5.Explain whether a mating between Canadian and Mexicanbutterflies would produce phenotypically normal offspring?arrow_forwardIn tomato plants, the genes for fruit colour (C), fruit fructose content (F), fruit length (L), and plant height (H) are all found on chromosome 4. Map distances between the four genes are shown below. Genes Distance in Map Units H and F 40 F and L 12 C and F 75 L and C 87 L and H 52 Sketch and label a gene map to identify the order of the four genes on chromosome 1 in tomato plants.arrow_forwardThe duck billed platypus is an unusual mammal. If you examine the sex chromosomes of a female platypus you will find a total of 10 X chromosomes. Examining a male platypus finds 5 X chromosomes and 5 Y chromosomes. No other combinations are seen. Each of these five X chromosomes is unique as is each Y chromosome (i.e. X1 pairs only with X1 or Y1, X2 with X2 or Y2 and so on). Why is this unusual? What unusual event must happen during meiosis in a male platypus? (Think carefully about what happens in meiosis 1)arrow_forward
- Create a chromosome map each set of three genes from the given information. a) The crossover frequency between gene A and gene B is 23%, the crossover frequency between gene B and gene C is 11%, and between gene A and C is 12%arrow_forwardWhich statement about the relationship between genetic map and physical map is FALSE? The correlation between Genetic map distance and Physical map distance is not absolute. Roughly speaking, for two genes on the same chromosome, the bigger their genetic map distance is, the bigger the physical map distance is. The genetic map is in a way a distorted picture of the physical map. 1 genetic map unit (1cM) always correlates with a certain distance on the physical chromosome.arrow_forwardBased on the data in Table 1, which individual(s) is/are heterozygous? Select all that apply a) B IV-8 b) C IV-3 c) B IV-9 d) A IV-3arrow_forward
- In a germline progenitor cell before DNA replication (2N), a translocation occurred between a telocentric and submetacentric chromosome resulting in a translocation heterozygote. The location of the translocation is illustrated below. Draw the Prophase I pairing conformation that would result from this translocation. The four types of chromosomes you have now can be labeled as follows: T-WT (telocentric wild type), T-TL (telocentric translocation), SM-WT (submetacentric wild type), and SM-TL (submetacentric translocation). Using these labels, list (please do not draw) the possible outcomes of Anaphase I and the possible phenotypes for each outcome. Please explain your reasoning for each phenotype in a few words. asaparrow_forwardA diploid species has 3 pairs of chromosomes in its somatic cells. In males, the first pair is large submetacentric[1]; the second is medium acrocentric[2], and the third is small telocentric[3]. In females, the first two pairs are like those of the males while the third is large metacentric[4][5], with satellite4 Illustrate the karyograms (drawing/picture of the chromosome) of the following: A triploid cell in females tetrasomic cell in males tetraploid cell in females [1] submetacentric --centrosome is just above the middle of the chromosome [2] acrocentric --centrosome is much higher location than submetacentric so that the “p” arm of the chromosome is much shorter than the q arm [3] telocentric --the centromere is at the end of the chromosome [4] metacentric --centrosome is in the middle of the chromosome; thus the “p-arm” and the “q-arm” or both arms of the chromosome are equal in length [5] satellite-a constriction in an arm of a chromosome, aside…arrow_forwardThe mutations called bobbed in Drosophila result from variable reductions (deletions) in the number of amplified genes coding for rRNA. Researchers trying to maintain bobbed stocks have often documented their tendency to revert to wild type in successive generations. Propose a mechanism based on meiotic recombination which could account for this reversion phenomenon. Why would wild-type flies become more prevalent in Drosophila cultures?arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage Learning