Exam 16: Variations in Chromosome Structure and Number

Why do polyploid individuals with an even number of chromosome sets have a higher likelihood of fertility than those with an odd number of chromosome sets?

The chemical colchicine prevents the formation of microtubules.It is commonly used in certain experimental procedures to cause changes in cellular chromosomes.Which of the following changes is it likely to be used to create?

A paracentric inversion heterozygote contains a normal chromosome with the long-arm gene order GENE and an inverted chromosome with the long-arm gene order GNEE.They form an inversion loop to pair during prophase I of meiosis.If a single crossover occurs between the G and the E segments of the loop,what will be the gene orders in the resulting recombinant dicentric chromosome and acentric fragment? Assume crossing over occurs at the four-strand stage involving two nonsister chromatids.

A(n)________ inversion includes the centromere.

No known living humans have one whole chromosome of a homologous pair of autosomes deleted from the genome.

A monosomic cell would produce gametes with how many chromosomes?

Which of the following traits is determined by programmed transposition?

Nondisjunction of chromosomes may result in

Both changes in chromosome number and chromosome structure are believed to have resulted in novel genomes,leading to new species.

Many scientists believe that the evolution of multigene families,such as the genes for hemoglobin,is a result of which type of genetic rearrangement?

Most monoploid individuals do not survive because

If a small region of a chromosome containing a non-essential gene is completely deleted,and an organism has two identical chromosomes with this deletion,then the organism

How can the banding patterns on Drosophila polytene chromosomes be used to aid deletion mapping of genes on the chromosomes?

A woman with normal vision,whose father has sex-linked color blindness,marries a man with normal vision.They have a son who has Klinefelter syndrome and is color blind.Describe precisely what kind of event could caused have his Klinefelter syndrome.

A human cell containing two sets of 23 chromosomes is

An X-linked homozygous color-blind woman gives birth to a son who is not color blind.He could have normal vision because he

In some fruit flies,an inversion involving the white-eyed locus (w)moves the w⁺gene from one end of the X chromosome to a location nearer to the centromere.Flies with a w⁺ or w⁺/w genotype are normally expected to have red eyes.However,in flies with the inversion,the eyes are mottled red and white.Explain why.

The diagram below shows a region near the center of a long arm of a chromosome.Assume that in the diagram below,every vertical hatch mark is 1 map unit from the next vertical hatch mark.The dashed double line represents an inversion.If you crossed this heterozygous individual with a normal homozygous recessive individual,and produced 1000 live offspring,how many would you expect to be Aa dd?

Approximately 15% of all human conceptions contain at least one chromosomal mutation.

In Drosophila melanogaster,polytene chromosomes are produced when