Deletion of a promoter-proximal element for a gene would have which of the follo
ID: 71980 • Letter: D
Question
Deletion of a promoter-proximal element for a gene would have which of the following effects? Expression of a particular phenotype can be dependent on whether the allele copy is maternal or paternal. For example, in Prader-Willi and Angelman's syndromes the gene region from one parent is deleted, the other parent's contribution has been silenced. This is an example of Engrailed (a gone involved in early development in Drosophila melanogaster) has an enhancer that regulates expression of the protein in a particular stripe of cells along the embryo A mutation in that enhancer would likely Have which of the following results? How do enhancers and response elements differ? Proteins such as the tryptophan repressor can be described as Familial Down syndrome is due to a reciprocal translocation event between chromosomes 14 and 21. Identify the type of segregation that would result in Down syndrome in one of the offspring of a cross between an individual with a normal karyotype and an individual who is a translocation heterozygote Triploids are usually sterile because homologous chromosomes fail to segregate properly producing non-viable gametes. A couple has a phonotypically normal son who is found to have the karyotype XYY. In what parent, and in what meiotic division, did the nondisjunction event occur?Explanation / Answer
1)
A group of transcription factors assemble at the promoter region of DNA, and bind to TATA box to change its shape. This event exposes the binding sites of other transcription factors. After several of these events, RNA polymerase binds and transcribes the gene. Therefore, deletion of a promoter proximal element for a gene would have reduced the rate of transcription initiation.
Thus, the correct option is (c).
2)
The peder-willi and angelman’s syndromes are cased due to genomic imprinting. Thus, the correct option is (a).
3)
The gene would not be transcribed in the particular stripe. Thus, the correct option is (b).
4)
The response elements respond to external signals. Thus, the correct option is (b).
5)
Proteins such as tryptophan repressor can be described as DNA-binding proteins. Thus, the correct option is (c).
6)
Individuals with Down syndrome carry three copies of chromosome 21 (trisomy). During meiosis, instead of the third copy being separate, “translocation” of this copy may occur and attached to another chromosome. In Down’s syndrome, usually translocation of 14/21 chromosomes occur. Hence, the chromosome number would be still 46 but, the chromosome 14 appears longer than the normal.
Thus, the correct option is (c) alternate.
7)
The given statement is true.
8)
Sometimes, error occurs in meiosis during the meiosis – I or II, i.e. during the separation of homologous chromosomes. These errors result in excess or less chromosomes in the daughter cell, and this is called “nondisjunctioning.”
Thus, the correct option is (a) father, meiosis-I.
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