You are encouraged to work in groups on these problems, but you should write you

Question

You are encouraged to work in groups on these problems, but you should write your own answers - do not copy directly from classmates or any other source. Please show your work and define your symbols clearly. A certain species of plant has 2n-16 chromosomes. How many chromosomes per cell would you expect to find in a somatic cell of an individual with each of the following changes? Monosomic Monoploid Nullisomic Triploid Trisomic Tetraploid Why are autopolyploid usually sterile, while allopolyploids are usually fertile? As part of your answer, explain what the difference is between these two types of polyploids.

Explanation / Answer

Please find the answers below:

The ploidy of the organism is given to be 2n = 16. This means that the diploid set of chromosomes are 16 in this organism. Based upon this information, the following answers can be deduced:

Part a: Monosomic : This arises due to complete or partial loss of one single chromosome fromt eh diploid set i.e. 2n-1. Thus the number of chromosomes will be 16-1 or 15.

Part b: Monoploid: Monoploidy refers to haploid set of chromosome number of the organism i.e. n. Here, monoploid number will be 2n/2 i.e. 16/2 or 8.

Part c: Nullisomic: A nullisomic chromosomal abberation refers to no net change in number of chromosomes, i.e. it will remain 2n = 16.

Part d: Triploid: A triploid set of chromosomes refers to thrice the number of haploid set of chromosomes. Thus, for the present case, since n=8, 3n or triploid number will be 8*3 = 24.

Part e: Trisomic: Trisomy refers to addition of a single chromosome to the total diploid set i.e. 2n+1. Thus, the total chromosomes in trisomic state will be 16+1 = 17.

Part f: Tetraploid: The tetraploid set of chromosomes refers to 4 times the total number of chromosomes of the haploid set i.e. 4*8 or 32.

Related Questions

Navigate

• Browse (All)
• Browse Y
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.