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

2:31 minutes

Problem 9c

Textbook Question

Mating between a male donkey (2n = 62) and a female horse (2n = 64) produces sterile mules. Recently, however, a very rare event occurred—a female mule gave birth to an offspring by mating with a horse.
Why is it very unlikely that the offspring will have fully horse-like genetic characteristics?

Verified step by step guidance

Understand the chromosomal differences between the donkey and horse: A male donkey has 62 chromosomes (2n=62), while a female horse has 64 chromosomes (2n=64). When they mate, the mule inherits one set of chromosomes from each parent, resulting in a hybrid with 63 chromosomes (not an even number).

Recognize why mules are sterile: The odd number of chromosomes (63) prevents proper pairing during meiosis, which is necessary for the production of viable gametes. This sterility is a key reason why mules cannot typically reproduce.

Consider the rare event of a female mule giving birth: In this case, the mule must have produced a viable egg. This could occur if the mule's chromosomes underwent an unusual event, such as nondisjunction or partial pairing, allowing the formation of a functional gamete.

Analyze the genetic contribution to the offspring: The mule's gamete would contain a mix of donkey and horse chromosomes. When this gamete combines with the horse's sperm (which contains only horse chromosomes), the offspring would inherit a combination of donkey and horse genetic material, making it unlikely to be fully horse-like.

Conclude why the offspring is unlikely to be genetically fully horse-like: The mule's gamete introduces genetic material from both donkey and horse origins. This hybridization ensures that the offspring will have a mix of genetic characteristics, rather than being purely horse-like.

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.

Hybrid Sterility

Hybrid sterility occurs when the offspring of two different species, such as a mule (a cross between a horse and a donkey), are unable to reproduce. This is often due to differences in chromosome number and structure, which can lead to improper pairing during meiosis, resulting in gametes that are not viable.

Chromosome Number and Compatibility

The male donkey has 62 chromosomes, while the female horse has 64, leading to mules having an intermediate chromosome number of 63. This odd number of chromosomes complicates meiosis, making it difficult for mules to produce gametes that can successfully combine with those of a horse, thus limiting the genetic diversity and compatibility of any potential offspring.

Genetic Recombination

Genetic recombination is the process by which genetic material is exchanged between chromosomes during meiosis. In the case of a mule mating with a horse, the uneven chromosome numbers hinder effective recombination, making it unlikely for the offspring to inherit a complete set of horse-like genetic traits, as the genetic material may not align properly during gamete formation.

Watch next

Master Aberrant Euploid with a bite sized video explanation from Kylia

Start learning

Related Videos

Related Practice

Textbook Question

If the haploid number for a plant species is 4, how many chromosomes are found in a member of the species that has one of the following characteristics? Explain your reasoning in each case.

Octaploidy

372

views

Textbook Question

If the haploid number for a plant species is 4, how many chromosomes are found in a member of the species that has one of the following characteristics? Explain your reasoning in each case.

Pentaploidy

470

views

Textbook Question

If the haploid number for a plant species is 4, how many chromosomes are found in a member of the species that has one of the following characteristics? Explain your reasoning in each case.

Diploidy

395

views

Textbook Question

Describe the origin of cultivated American cotton.

574

views

Textbook Question

Mating between a male donkey (2n = 62) and a female horse (2n = 64) produces sterile mules. Recently, however, a very rare event occurred—a female mule gave birth to an offspring by mating with a horse.

How many chromosomes does the mule–horse offspring carry?

4167

views

Textbook Question

Determine how many chromosomes are in the mule karyotype, and explain why mules are generally sterile.

426

views

Textbook Question

The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

Summarize what is known about the location and genes found within the DSCR.

396

views

Textbook Question

How might those genes lead to the main symptoms of Down syndrome?

463

views

Show more practices