40 Questions
What was the significance of Morgan's discovery of the eye colour mutant?
It led to the development of the chromosome theory of inheritance.
What do the superscript '+' and '-' symbols denote in Drosophila allele notation?
Wild-type and mutant alleles, respectively.
What is the significance of correlating the sex of flies with the behaviour of alleles of the eye colour gene?
It provides evidence for the chromosome theory of inheritance.
What is the symbol for the mutant white eyes allele in Drosophila?
w
Who developed the simple notation for alleles?
Mendel
What is the expected ratio of phenotypes if the genes assort independently?
1:1:1:1
What did Morgan's data suggest about the genes controlling body colour and wing size?
That they are genetically linked
Why are closely physically linked genes not expected to assort independently?
Because they are located close together on the same chromosome and move through meiosis as a unit
What is the significance of sister chromatids forming chiasmata in the same homologous chromosome?
It has no genetic consequences because they are identical.
What is the result of recombination between linked genes?
The genes are separated and move through meiosis independently
What is the recombination rate between the b and vg genes in Drosophila melanogaster?
17%
What is the significance of the experiment with Drosophila melanogaster?
It demonstrated the concept of genetic linkage
Who developed the idea of a genetic map in 1913?
Alfred H. Sturtevant
What is the purpose of recombination rates in genetics?
To determine the genetic map of genes on a chromosome
What is the relationship between the genes b, vg, and cn?
They are linked genes on the same chromosome
What is the genetic makeup of the wild-type females used in the experiment?
b+ b+ vg+ vg+
Which of the following statements is true about the genes controlling body colour and wing size?
They are autosomal genes.
What is the effect of the vg allele on the wing size of Drosophila melanogaster?
It results in vestigial wings.
What is the relationship between the b+ and b alleles?
b is recessive to b+.
What is the purpose of crossing wild-type females with males having both mutant phenotypes in the experiment?
To study the inheritance pattern of autosomal genes.
What can be concluded from the image of the homologous chromosomes with a specific gene tagged with a fluorescent yellow dye?
Genes are DNA sequence segments located on chromosomes.
What was the significance of Thomas Hunt Morgan's work in the early 1900s?
He provided solid evidence associating a specific gene with a specific chromosome.
What is the relationship between genes and chromosomes?
Genes are located on chromosomes.
What is the expected ratio of parental phenotypes in the offspring if linkage is complete between two genes?
1:1
What can be inferred about the image of the homologous chromosomes?
The chromosomes have duplicated and each has two sister chromatids.
What is the process by which recombinant chromosomes and phenotypes are generated?
Genetic recombination
What is the term for the X-shaped structure between chromatids in a tetrad during meiosis?
Chiasma
What is the concept that describes the connection between genes and chromosomes?
The chromosomal theory of inheritance.
What is the result of crossing-over between linked genes?
Recombinant phenotypes
What is the name of the process by which alleles from different genes are brought together in new combinations?
Genetic recombination
What is the term for the normal phenotype for a character in Drosophila genetics?
Wild type
How many chromosomes are present in a haploid gamete in Drosophila melanogaster?
4
What is the sex chromosome composition of a male Drosophila melanogaster?
XY
What was the significance of Morgan's discovery of an eye color mutant in Drosophila melanogaster?
It showed that genes are located on specific chromosomes
How many pairs of chromosomes are present in a diploid Drosophila melanogaster cell?
4
What is the term for an alternative trait to the wild type in Drosophila genetics?
Mutant phenotype
What is the probability of a sperm having an X chromosome in Drosophila melanogaster?
50%
What is the sex chromosome composition of a female Drosophila melanogaster?
XX
What is assumed to be the origin of mutant alleles in Drosophila genetics?
Changes in the wild type allele
What is the total number of chromosomes in a diploid Drosophila melanogaster cell?
8
Learn about the notation system used to describe gene alleles in Drosophila melanogaster, including the history and rules behind the notation. Understand how Morgan's system differs from Mendel's simple notation. Test your knowledge of genetics and biotech!
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