Genetic Linkage in Drosophila Melanogaster

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What is the significance of a 50% recombination rate between two genes?

The genes are always unlinked and will never be inherited together.
The genes are located on the same chromosome but are very close together.
The genes are always linked and will never separate during crossing over.
The genes are on different chromosomes or are located far apart on the same chromosome. (correct)

What is the unit of measurement for recombination rates?

CentiMorgan (cM) (correct)
Morgan
Recombination fraction
Linkage frequency

What can be inferred about the relative positions of the eye colour, body colour, and wing size genes based on their recombination rates?

The genes are equally spaced from each other.
The eye colour and wing size genes are closest together.
The body colour and wing size genes are closest together.
The eye colour and body colour genes are closest together. (correct)

What is the relationship between recombination rate and physical distance between genes on a chromosome?

A lower recombination rate indicates genes are closer together. (A) Signup and view all the answers

What is the purpose of generating a genetic linkage map?

To illustrate the relative positions of genes on a chromosome. (B) Signup and view all the answers

What is the ratio of parental phenotypes expected in the offspring if linkage is complete?

1:1 (A) Signup and view all the answers

What is the primary reason for the absence of genetic consequences in chiasmata formation between sister chromatids in the same homologous chromosome?

They are identical (D) Signup and view all the answers

What is the significance of the recombination rate of 17% in the Drosophila melanogaster cross?

It indicates that the genes are linked with a distance of 17 centiMorgan (C) Signup and view all the answers

What is the process called when alleles from different genes come together in new combinations?

Genetic recombination (C) Signup and view all the answers

What is the term for the visible crossing-over points between chromatids in a tetrad?

Chiasmata (D) Signup and view all the answers

What is the purpose of creating a genetic map of genes on a chromosome?

To understand the inheritance patterns of traits (B) Signup and view all the answers

Which of the following is a consequence of independent assortment of genes?

Genes are inherited independently (B) Signup and view all the answers

What is the purpose of creating genetic linkage maps?

To locate genes on a chromosome and measure the distances between them (B) Signup and view all the answers

What is the unit of measurement used to express the distance between genes on a chromosome?

Centimorgan (D) Signup and view all the answers

What is the unit of measurement used to express the distance between genes on a genetic map?

CentiMorgan (B) Signup and view all the answers

What is the chromosomal location of the genes OPN1MW and OPN1LW?

BTAX (C) Signup and view all the answers

Which of the following is a characteristic of linked genes?

They are physically close to one another on the same chromosome (C) Signup and view all the answers

What is the main reason why the wing size and body colour genes in Drosophila melanogaster are not sex-linked?

Because they are on the same autosomal chromosome (A) Signup and view all the answers

What is the genotype of the wild type females used in the experiment by Thomas Hunt Morgan and his team?

b+ b+ vg+ vg+ (C) Signup and view all the answers

What is the phenomenon demonstrated by Thomas Hunt Morgan in Drosophila melanogaster?

Genetic Linkage (D) Signup and view all the answers

What is the purpose of crossing wild type females with males that have both mutant phenotypes in the experiment?

To demonstrate genetic linkage between the two genes (C) Signup and view all the answers

What is the significance of the superscript '+' symbol in Drosophila melanogaster gene notation?

It identifies the wild type allele for the eye color gene (A) Signup and view all the answers

What is the unit of measurement for the distance between two genes on a genetic linkage map?

CentiMorgan units (B) Signup and view all the answers

What is the relationship between the number of genes and the number of chromosomes?

The number of genes is much larger than the number of chromosomes (D) Signup and view all the answers

What is the underlying principle of independent assortment, which is not observed in the case of genetic linkage?

Genes are distributed randomly during gamete formation (A) Signup and view all the answers

What did Morgan's discovery of an eye color mutant lead to?

The first concrete demonstration that a gene is located on a specific chromosome (C) Signup and view all the answers

What is the significance of the allele symbol 'w' in Drosophila melanogaster gene notation?

It represents the mutant allele for the eye color gene (C) Signup and view all the answers

What is the relationship between the behavior of the sex chromosomes and the behavior of the two alleles of the eye color gene?

The behavior of the sex chromosomes can be correlated with the behavior of the two alleles of the eye color gene (C) Signup and view all the answers

What is the purpose of correlating the behavior of the sex chromosomes with the behavior of the two alleles of the eye color gene?

To demonstrate the chromosome theory of inheritance (B) Signup and view all the answers

What is the consequence of independent assortment of genes on a chromosome?

The recombination of alleles from different genes in new combinations (C) Signup and view all the answers

What is the purpose of the Ishihara chart?

To diagnose sex-linked color blindness (D) Signup and view all the answers

What is the result of Morgan's discovery of an eye color mutant in terms of genetic mapping?

The first concrete demonstration that a gene is located on a specific chromosome (B) Signup and view all the answers

What is the relationship between the genetic distance between two genes and the recombination rate?

The genetic distance between two genes is inversely proportional to the recombination rate (D) Signup and view all the answers

What is the significance of the centiMorgan unit in genetic mapping?

It is a measure of genetic distance between two genes (B) Signup and view all the answers

What is the result of correlating the behavior of the sex chromosomes with the behavior of the two alleles of the eye color gene?

The support for the chromosome theory of inheritance (C) Signup and view all the answers

What is the expected ratio of phenotypes if genes assort independently?

1:1:1:1 (C) Signup and view all the answers

What is the primary reason for the underrepresentation of recombinant phenotypes in Morgan's experiment?

Genes controlling body color and wing size are genetically linked (D) Signup and view all the answers

What is the term used to describe the process of recombination between linked genes?

Crossing-over (C) Signup and view all the answers

What is the unit of measurement used to express the distance between two genes on a chromosome?

CentiMorgan units (D) Signup and view all the answers

What is the term used to describe the process of genes moving through meiosis as a unit without being separated by recombination?

Genetic linkage (B) Signup and view all the answers