Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 17, Problem 37P
Persimmons (Diospyros lotus) are dioecious plants, meaning that male (XY) and female (XX) flowers exist on separate plants. Male persimmon flowers have rudimentary, nonfunctional carpels (the female sex organ that includes the ovary), while female flowers have stamens and anthers (male sex organs), but no pollen is produced. Remarkably, sex determination in D. lotus is controlled by a Y-linked miRNA gene called OGI (male tree in Japanese), whose target mRNA is encoded by an autosomal gene called MeGI (female tree).
a. | What features of the OGI transcript base sequence might have suggested to the investigators that OGI encodes a miRNA? |
b. | RNA-Seq experiments detected high levels of MeGI mRNA in female sex organs but low levels in male sex organs. Suggest a molecular mechanism by which the OGI miRNA could regulate MeGI gene expression. |
Integrating transgenes into the D. lotus genome is difficult. Therefore, to examine the function of MeGI, the scientists constructed a transgene that overexpresses MeGI and used it to transform Arabidopsis thaliana, a plant species more amenable to such studies. Arabidiposis have so-called perfect flowers—individual flowers have both male and female structures. MeGI overexpression in the transformants sterilized the anthers, but the carpels were unaffected and functional. | |
c. | What do you predict would happen if the Arabidopsis transformants also contained a transgene that overexpressed OGI? |
d. | The MeGI protein is a homeobox transcription factor. What do the results with transformed Arabidopsis suggest is one role of this protein in persimmon sex determination? |
e. | Speculate about possible mechanisms that could account for the rudimentary development of the nonfunctional carpels in male persimmon flowers. Could any of these mechanisms involve OGI and MeGI? |
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Chapter 17 Solutions
Genetics: From Genes to Genomes
Ch. 17 - For each of the terms in the left column, choose...Ch. 17 - For each of the following types of gene...Ch. 17 - List five events other than transcription...Ch. 17 - Which eukaryotic RNA polymerase RNA pol I, pol II,...Ch. 17 - As shown in the following diagram, a single...Ch. 17 - You have synthesized an enhancerless GFP reporter...Ch. 17 - Prob. 7PCh. 17 - Prob. 8PCh. 17 - A single UAS regulates the expression of three...Ch. 17 - MyoD is a transcriptional activator that turns on...
Ch. 17 - a. Assume that two transcription factors are...Ch. 17 - Prob. 12PCh. 17 - In Problem 12, you identified a genomic region...Ch. 17 - Prob. 14PCh. 17 - Prob. 15PCh. 17 - Genes in both prokaryotes and eukaryotes are...Ch. 17 - Prob. 17PCh. 17 - Lysine 4 of histone H3 H3K4 is methylated in the...Ch. 17 - J.T. Lis and collaborators have developed an...Ch. 17 - Hydatiform moles are growths of undifferentiated...Ch. 17 - Prader-Willi syndrome is caused by a mutation in...Ch. 17 - The human IGF2 gene is autosomal and maternally...Ch. 17 - Follow the expression of a paternally imprinted...Ch. 17 - Reciprocal crosses were performed using two inbred...Ch. 17 - Interestingly, imprinting can be tissue-specific....Ch. 17 - Prob. 26PCh. 17 - A method for detecting methylated CpGs involves...Ch. 17 - Honeybees Apis mellifera provide a striking...Ch. 17 - Consider the experiment in Fig. 17.24, where the...Ch. 17 - A protein or RNA that regulates gene expression in...Ch. 17 - a. How can a single eukaryotic gene give rise to...Ch. 17 - A hunchback gene, a gene necessary for proper...Ch. 17 - You know that the mRNA and protein produced by a...Ch. 17 - You are studying a transgenic mouse strain that...Ch. 17 - Prob. 35PCh. 17 - Scientists have exploited the siRNA pathway to...Ch. 17 - Persimmons Diospyros lotus are dioecious plants,...Ch. 17 - Drosophila females homozygous for loss-of-function...Ch. 17 - The text has discussed the RNA-Seq technique,...Ch. 17 - Researchers know that Fru-M controls male sexual...Ch. 17 - The Drosophila gene Sex lethal Sxl is deserving of...Ch. 17 - Figure 17.29 shows that the Sxl protein binds to...
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