Exam 8: Chromosome Mutations: Variation in Number and Arrangement

Assume that a species has a diploid chromosome number of 24.The term applied to an individual with 36 chromosomes would be triploid.

Fragile X syndrome (or Martin-Bell syndrome)is the most common form of inherited mental retardation in humans.Is it more common in males or females? What is FMR1?

Trisomics are observed in humans; monosomics are not.Why?

What explanation is generally given for lethality of monosomic individuals?

Assume that an organism has a diploid chromosome number of 14.There would be 28 chromosomes in a tetraploid.

Assume that an organism has a haploid chromosome number of 7.There would be 14 chromosomes in a monoploid individual of that species.

Deletions are chromosomal aberrations in which some portion of a chromosome is missing.Describe a method using Drosophila deletions to determine the actual,physical location of a gene.

Familial Down syndrome is caused by a translocation involving chromosome 21.