You may purchase mutant and wild-type flies online at a nearby laboratory, or you may purchase just the mutants and collect the wild-type ones yourself.
The chromosomes present in the diploid cells of the majority of the sexually reproducing animals are of two types: Sex chromosomes also carry some genes for non-sexual characters such as colour blindness and haemophilia. Such genes which are always associated with sex chromosomes are called sex-linked genes.
In man and Drosophila the sex chromosomes X and Y are unequal in size and shape, X being larger and rod shaped whereas Y is small and slightly curved.
In birds and butterflies the sex chromosomes Z and W are also unequal in shape and size, Z being larger than W. In Mendelian pattern of inheritance, the genes for contrasting characters were located on autosomes but not on the sex chromosomes.
Secondly, the result of reciprocal cross is same as normal cross which is not the case with sex linked inheritance. There are three types of sex-linked genes depending upon their association with particular chromosome.
They are as follows: Such genes are called incomplete sex-linked genes. In order to understand the inheritance of character present in sex chromosomes, let us understand transmission of X-chromosome from male individual in Drosophila or in man.
The X-chromosome from male individual will always pass to the daughter, while X-chromosomes from female individual will be distributed equally among the daughter and sons Fig. A character from the father goes to the daughter F1 and then from daughter to grandson in the next generation F2.
Such type of inheritance is also called as criss-cross inheritance. In this type of inheritance result of the reciprocal crosses are not identical as in case with Mendelian crosses. Morgan for the first time discovered sex-linkage in Drosophila melanogaster.
Morgan when experimenting noted the sudden appearance of one white-eyed male mutant form in the culture of normal red-eyed Drosophila.
This white-eyed male was crossed with red eyed female. The F1 flies both male and female were all red-eyed indicating that white eye colour is recessive to the normal red eye colour.
When these F1 flies were inter-crossed freely, the red-and white-eyed flies appeared in the ratio 3: White- eyed flies were male. Among the red eyed flies two-third were female and one-third were male. If a reciprocal cross is performed between white eyed female and red eyed male individual, all female individuals in Ft generation are red eyed and all male individuals, are white eyed.
The inheritance of white-eye colour in Drosophila can be explained on the basis of the following assumptions: It transmits one gene for white eye colour w to each offspring. The daughter in turn passes this gene to her sons F2 generation. The character thus seems to alter or cross from one sex to the other in its passage from generation to generation.
In other words, character is transferred from mother to son and never from father to the son. Characteristics of Sex Linked Inheritance: Sex Linkage in Man:In this experiment, the inheritance patterns of different fly traits found in Drosophila melanogaster were determined though reciprocal crosses of parental flies and their F1 progeny.
Materials and Methods. Six different variations of drosophila melanogaster were distributed to teams in vials containing about 10 adult flies each.
The six variations of . The fruit fly, also known as Drosophila melanogaster, has the longest history in genetics and research out of all the model organisms. Although generally considered a pest by farmers because they lay their eggs in ripening fruit, in the laboratory the fruit fly has proved to be one of the most.
The fruit fly, or the Drosophila melanogaster, was used in this experiment to study patterns of inheritance. It only takes a fruit fly 14 days to develop from an egg to an adult and then 12 hours before they become reproductive, so these factors made the fruit fly a good species to study, because we.
Genetics Basics - Lesson 3: Modes of Inheritance. Modes of Inheritance. Inheritance patterns describe how a disease is transmitted in families. Affected males transmit the disease allele to all of their daughters, who are then carriers, but to none of their .
Objective: Students will learn and apply the principles of Mendelian inheritance by experimentation with the fruit fly Drosophila melanogaster.
Students will make hypotheses for monohybrid, dihybrid and sex-linked traits and test their hypotheses by selecting fruit flies with different visible mutations, mating them, and analyzing the.
The study of inheritance began with Gregor Johann Mendel, who published his work in Then, during the early s, Thomas Hunt Morgan started studying mutations in Drosophila flies.
Based on research by Morgan and his students, the chromosome theory of inheritance was proposed.