a) Considering random segregation of the chromosome, determine the genotype and proportion of the sperm produced by the trisomic male fruit fly with genotype ++ey . b) Determine the expected ratio of the eyeless to normal eyed flies produced by the union of the sperm with the egg having genotype eyey producing an eyeless phenotype . Introduction: The segregation of the chromosome during cell division is an important phenomenon. If the chromosome fails to segregate properly, it is called non-disjunction, and it could have resulted in the daughter cell with one extra chromosome ( n+1 ) and the other with a missing chromosome ( n-1 ) condition. The cell with improper distribution of the chromosomes may reduce their survival rate as compared to the normal cell. In the germ cells, non-disjunction results in the formation of gametes with extra or missing chromosomes which leads to the production of aneuploidy gametes. Germ cells, egg or sperms, are haploid cells, containing a single pair of chromosome. The condition of the presence of extra chromosome ( 2n+1 ) in the zygote due to the union of aneuploid gamete with a normal haploid gamete is known as trisomy.

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Chapter 13, Problem 17P

Summary Introduction

To analyze:

a) Considering random segregation of the chromosome, determine the genotype and proportion of the sperm produced by the trisomic male fruit fly with genotype ++ey.

b) Determine the expected ratio of the eyeless to normal eyed flies produced by the union of the sperm with the egg having genotype eyey producing an eyeless phenotype.

Introduction:

The segregation of the chromosome during cell division is an important phenomenon. If the chromosome fails to segregate properly, it is called non-disjunction, and it could have resulted in the daughter cell with one extra chromosome (n+1) and the other with a missing chromosome (n-1) condition.

The cell with improper distribution of the chromosomes may reduce their survival rate as compared to the normal cell. In the germ cells, non-disjunction results in the formation of gametes with extra or missing chromosomes which leads to the production of aneuploidy gametes. Germ cells, egg or sperms, are haploid cells, containing a single pair of chromosome. The condition of the presence of extra chromosome (2n+1) in the zygote due to the union of aneuploid gamete with a normal haploid gamete is known as trisomy.

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