Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

6. Chromosomal Variation

Chromosomal Mutations: Aberrant Euploidy

Genetics

6. Chromosomal Variation

Chromosomal Mutations: Aberrant Euploidy

Previous problemNext problem

1:35 minutes

Problem 22a

Textbook Question

Two experimental varieties of strawberry are produced by crossing a hexaploid line that contains 48 chromosomes and a tetraploid line that contains 32 chromosomes. Experimental variety 1 contains 40 chromosomes, and experimental variety 2 contains 56 chromosomes.
Do you expect both experimental lines to be fertile? Why or why not?

Verified step by step guidance

Determine the ploidy levels of the parent lines. The hexaploid line has 48 chromosomes, so the base chromosome number (x) is 48 ÷ 6 = 8. Similarly, the tetraploid line has 32 chromosomes, so its base chromosome number is 32 ÷ 4 = 8. Both lines share the same base chromosome number (x = 8), which is important for compatibility during hybridization.

Analyze the chromosome number of experimental variety 1 (40 chromosomes). Since 40 is not a multiple of the base chromosome number (8), this suggests that the chromosomes may not pair evenly during meiosis, leading to potential fertility issues.

Analyze the chromosome number of experimental variety 2 (56 chromosomes). Since 56 is a multiple of the base chromosome number (8), this suggests that the chromosomes can pair evenly during meiosis, which is more likely to result in fertility.

Explain the relationship between chromosome pairing and fertility. Fertility in polyploid organisms depends on the ability of chromosomes to pair evenly during meiosis. Uneven chromosome numbers (e.g., 40 in variety 1) can lead to unbalanced gametes and reduced fertility, while even chromosome numbers (e.g., 56 in variety 2) are more likely to produce balanced gametes and maintain fertility.

Conclude by stating that experimental variety 1 is unlikely to be fertile due to its uneven chromosome number, while experimental variety 2 is more likely to be fertile because its chromosome number allows for proper pairing during meiosis.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ploidy Levels

Ploidy refers to the number of sets of chromosomes in a cell. In this case, the hexaploid line has six sets (48 chromosomes) and the tetraploid line has four sets (32 chromosomes). Understanding ploidy is crucial because it affects the fertility and viability of the offspring produced from these crosses, as mismatched ploidy levels can lead to complications in meiosis.

Chromosome Number and Fertility

The number of chromosomes in an organism can significantly influence its fertility. In this scenario, experimental variety 1 has 40 chromosomes, while variety 2 has 56. Fertility is often compromised when the chromosome numbers of the parents differ significantly, as it can lead to unbalanced gametes and difficulties during meiosis, potentially resulting in sterile offspring.

Meiosis and Gamete Formation

Meiosis is the process by which gametes (sperm and eggs) are produced, involving two rounds of cell division that reduce the chromosome number by half. For successful reproduction, gametes must have compatible chromosome numbers. In this case, the differing chromosome counts in the experimental varieties may hinder proper pairing and segregation during meiosis, affecting the fertility of the resulting hybrids.

Watch next

Master Aberrant Euploid with a bite sized video explanation from Kylia

Start learning

Related Videos

Related Practice

Textbook Question

Dr. Ara B. Dopsis has an idea he thinks will be a boon to agriculture. He wants to create the 'pomato,' a hybrid between a tomato (Lycopersicon esculentum) that has 12 chromosomes and a potato (Solanum tuberosum) that has 48 chromosomes. Dr. Dopsis is hoping his new pomato will have tuber growth like a potato and the fruit production of a tomato. He joins a haploid gamete from each species to form a hybrid and then induces doubling of chromosome number.

How many chromosomes will the polyploid have after chromosome doubling?

403

views

Textbook Question

The primrose, Primula kewensis, has 36 chromosomes that are similar in appearance to the chromosomes in two related species, P. floribunda (2n=18) and P. verticillata (2n=18). How could P. kewensis arise from these species? How would you describe P. kewensis in genetic terms?

770

views

Textbook Question

Certain varieties of chrysanthemums contain 18, 36, 54, 72, and 90 chromosomes; all are multiples of a basic set of nine chromosomes. How would you describe these varieties genetically? What feature do the karyotypes of each variety share? A variety with 27 chromosomes has been discovered, but it is sterile. Why?

426

views

Textbook Question

In Drosophila, seven partial deletions (1 to 7) shown as gaps in the following diagram have been mapped on a chromosome. This region of the chromosome contains genes that express seven recessive mutant phenotypes, identified in the following table as a through g. A researcher wants to determine the location and order of genes on the chromosome, so he sets up a series of crosses in which flies homozygous for a mutant allele are crossed with flies homozygous for a partial deletion. The progeny are scored to determine whether they have the mutant phenotype ('m' in the table) or the wild-type phenotype ('+' in the table). Use the partial deletion map and the table of progeny phenotypes to determine the order of genes on the chromosome.

535

views

Textbook Question

Two experimental varieties of strawberry are produced by crossing a hexaploid line that contains 48 chromosomes and a tetraploid line that contains 32 chromosomes. Experimental variety 1 contains 40 chromosomes, and experimental variety 2 contains 56 chromosomes.

How many chromosomes from the tetraploid lines are contributed to experimental variety 1? To experimental variety 2?

376

views

Textbook Question

How many chromosomes from the hexaploid line are contributed to experimental variety 1? To experimental variety 2?

561

views

Multiple Choice

Which type of chromosomal aberration is most likely to result in a gain of function?

views

Multiple Choice

Which of the following diseases is caused by a chromosomal abnormality present before birth?