Watch this video and answer lonloung q \"Genetic Toolkit\"- http://www.pbslearni
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Watch this video and answer lonloung q "Genetic Toolkit"- http://www.pbslearningmedia.org/resource/tde02.sci.life.gen.genetictoolkit/geneti the Research in the development of fruit flies led to which one of the following important but controversial discoveries? I. . a. Different segments of the fruit fly embryo only possess the genes that are important to that segment during development b. Nervous tissue develops early and directs development of other parts of the fruit fly . bryo c Each segment of a fruit fly embryo is being directed during development by a single e that activates other genes. . d. Development of segments in the fruit fly embryo are influenced mostly by neighboring scgments. 2. We have discovered that some genes, called Hox (or homeobox) genes, control expression of other genes during development. Based on this observation, we can predict a. that a Hox gene transplanted from one species to another will still control expression of . other genes. b. that natural selection will not allow mutation in Hox genes. . c. that the development of complex features such as eyes can be driven by expression of Hox genes . d. that Hox genes are found only in advanced organisms such as vertebrates. . c.both b and d are correct . f.both a and c are correct 3. Homologs of the genes involved in development (the genetic "toolkit") have been found in all animals. This provides evidence that .a.the genetic "toolkit" for animal development likely was present in a common ancestor . b convergent evolution has resulted in similarities of genetic information in all modern . c.natural selection must not be operating on the genetic "toolkit," otherwise we would . d.mutations do not occur in genes in the "toolkit." to all modern animals. animals. see differences in the genes from one animal to another.Explanation / Answer
ANSWER)
1) D, Development of segments in fruit fly is mostly influenced by neighboring segments.
Drosophila segmentation is influenced by three types of genes-maternal effect genes, Segmentation genes, homeotic genes.
These genes produce mRNAs which influence the polarity and pattern formation in fruit fly. They are derived from the ovum of mother. These genes influence each other to form the head, thorax and abdomen region.
Examples of maternal effect genes are Bicoid, caudal, hunchback and Nanos.
Examples of segmentation(gap) genes are- Knirps, Kruppel, Giant, tailless, hunchback.
Homeotic genes are present as a cluster of Antennapedia an Bithorax region.
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2) A and C are correct
HOX genes are highly conserved among species and a gene from mouse can be inserted in drosophila and still guide the expression and formation of eye.
HOX gene help turn on the genes responsible for normal eye development
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3) A is correct.
The genetic toolkit for animal development was present in a common ancestor. As these genes are crucial for development, they are conserved or relatively less mutation occur in these genes. Thus, there is homology between species when it comes to these genes.
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