Textbook Question
For a species with a diploid number of 18, indicate how many chromosomes will be present in the somatic nuclei of individuals that are haploid, tetraploid, trisomic, and monosomic.
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Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement
Klug10th EditionEssentials of GeneticsISBN: 9780135588789
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Table of contents
- Ch. 1 - Introduction to Genetics16
- Ch. 2 - Mitosis and Meiosis28
- Ch. 3 - Mendelian Genetics37
- Ch. 4 - Modification of Mendelian Ratios53
- Ch. 5 - Sex Determination and Sex Chromosomes32
- Ch. 6 - Chromosome Mutations: Variation in Number and Arrangement37
- Ch. 7 - Linkage and Chromosome Mapping in Eukaryotes36
- Ch. 8 - Genetic Analysis and Mapping in Bacteria and Bacteriophages24
- Ch. 9 - DNA Structure and Analysis38
- Ch. 10 - DNA Replication29
- Ch. 11 - Chromosome Structure and DNA Sequence Organization22
- Ch. 12 - The Genetic Code and Transcription36
- Ch. 13 - Translation and Proteins27
- Ch. 14 - Gene Mutation, DNA Repair, and Transposition34
- Ch. 15 - Regulation of Gene Expression in Bacteria22
- Ch. 16 - Regulation of Gene Expression in Eukaryotes37
- Ch. 17 - Recombinant DNA Technology27
- Ch. 18 - Genomics, Bioinformatics, and Proteomics30
- Ch. 19 - The Genetics of Cancer21
- Ch. 20 - Quantitative Genetics and Multifactorial Traits37
- Ch. 21 - Population and Evolutionary Genetics45
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Klug 10th EditionCh. 6 - Chromosome Mutations: Variation in Number and ArrangementProblem 7
Klug 10th EditionCh. 6 - Chromosome Mutations: Variation in Number and ArrangementProblem 7Chapter 6, Problem 7
Why do human monosomics most often fail to survive prenatal development?
Verified step by step guidance1
Understand that monosomy refers to the condition where an individual has only one copy of a particular chromosome instead of the usual two.
Recognize that chromosomes carry many essential genes, and having only one copy (monosomy) means there is a loss of genetic material, which can disrupt normal development.
Consider the concept of gene dosage, which is the number of copies of a gene present in a cell; proper gene dosage is critical for normal cellular function and development.
Realize that in humans, most autosomal monosomies lead to severe imbalances in gene dosage, causing developmental abnormalities that are usually incompatible with life.
Conclude that because of these severe genetic imbalances, human monosomics typically fail to survive prenatal development, leading to early miscarriage or embryonic lethality.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Monosomy and Chromosomal Imbalance
Monosomy refers to the loss of one chromosome from a pair, leading to a chromosomal imbalance. This imbalance disrupts the normal dosage of genes, causing developmental abnormalities. In humans, most monosomies are lethal because essential genes are missing, impairing vital biological processes.
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Chromosome Structure
Gene Dosage Sensitivity
Gene dosage sensitivity means that the correct number of gene copies is crucial for normal development. Losing one chromosome reduces gene dosage by half for many genes, which can severely affect cellular function and organismal viability. This sensitivity explains why monosomic embryos often fail to develop properly.
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09:09Mapping Genes
Prenatal Development and Viability
Prenatal development is a critical period where precise genetic regulation is essential for growth and differentiation. Chromosomal abnormalities like monosomy often disrupt these processes, leading to miscarriage or stillbirth. Only a few monosomies, such as Turner syndrome (monosomy X), are compatible with survival due to unique genetic mechanisms.
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08:30Genetics of Development
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What evidence suggests that Down syndrome is more often the result of nondisjunction during oogenesis rather than during spermatogenesis?
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Contrast the fertility of an allotetraploid with an autotriploid and an autotetraploid.
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Predict how the synaptic configurations of homologous pairs of chromosomes might appear when one member is normal and the other member has sustained a deletion or duplication.
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Inversions are said to 'suppress crossing over.' Is this terminology technically correct? If not, restate the description accurately.
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