Concept explainers
To review: The fact that “inversions and reciprocal translocations are less lethal than aneuploidy, duplication, deletions and nonreciprocal translocation”.
Concept introduction: The aberration in chromosome structure and function can be caused due to aneuploidy, duplication, deletions and translocations. These can alter the chromosome to cause genetic disorders. Aneuploidy is a type of chromosomal alteration in which the number of chromosome changes. Duplication refers to the repetition of a segment on the chromosome. Deletion is the removal of a segment of a chromosome and the translocation is the transfer of a segment from one locus to another locus on the chromosome. Inversion is the insertion of a segment of chromosome in reverse order.
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EBK CAMPBELL BIOLOGY
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- What is a balanced chromosomal rearrangement?arrow_forwardWhat are the possible effects of chromosomal rearrangements?arrow_forwardA diploid individual is heterozygous for a chromosome rearrangement. The original chromosome and its rearranged homolog have the following segments, where ∙ represents a centromere: A B ∙ C D E F G A B ∙ C F E D G While paired in prophase I, a single crossing-over occurs between segment E and segment D of the paired chromosomes. Describe the unusual crossing-over structure that forms as a result.What gamete types will result from crossing over when meiosis is complete? please asaparrow_forward
- What is the most common autosome aneuploidy?arrow_forwardWhy are the X and Y chromosomes not considered homologous even though they recombine at the PAR region?arrow_forwardA normal mother has translocations on chromosomes 14:21. With respect to chromosomes 14:21, how many combinations of chromosomes are possible? How many gametes are viable? If the woman has children with an normal father, what is the probability that there is a daughter with Down Syndrome or a son with an unaffected phenotype?arrow_forward
- Inversions are known to affect crossing-over. The following homologs have the indicated order (the filled and open circles indicate centromeres): • (A B C D E) o (A D C B E) b. Diagram the alignment of these chromosomes during meiosis.arrow_forwardContrast the genetic composition of gametes derived from tetrads of inversion heterozygotes where crossing over occurs within a paracentric versus a pericentric inversion.Contrast the genetic composition of gametes derived from tetrads of inversion heterozygotes where crossing over occurs within a paracentric versus a pericentric inversion.arrow_forwardA phenotypically abnormal individual has a phenotypically normalfather with an inversion on one copy of chromosome 7 and a phenotypicallynormal mother without any changes in chromosomestructure. The orders of genes along the two copies of chromosome7 in the father are as follows: R T D M centromere P U X Z C (normal chromosome 7)R T D U P centromere M X Z C (inverted chromosome 7) The phenotypically abnormal offspring has a chromosome 7 withthe following order of genes: R T D M centromere P U D T R Using a sketch, explain how this chromosome was formed. In youranswer, explain where the crossover occurred (i.e., between whichtwo genes).arrow_forward
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