**Genetics Exercise: Mapping X-Linked Genes in Drosophila** **Overview:**Males of many diploid species, such as humans, have X and Y sex chromosomes. They are hemizygous for most X-linked genes, expressing X-linked alleles, whether dominant or recessive. In Drosophila (fruit fly), test crosses are used to explore X-linked genes in females. By observing male offspring's phenotypes, gene mapping is achieved, naming the gene after the mutant phenotype.**Activity:**Establish gene order and map distances between three X-linked genes in Drosophila:- **fruitless (f)**: Bisexual phenotype.- **lush (l)**: Heightened ethanol response.- **ken&barbie (kb)**: Lacks external genitalia.These genes are expressed as recessive mutant alleles. Flies' genotypes and phenotypes for gene mapping in this exercise are fictional.**Experimental Design:**1. **P1 Generation:** - **Cross:** Homozygous F KB l / F KB l females X f kb L / Y males. - **Result:** F1 female progeny.2. **F2 Generation:** - F1 females mated with males.**Phenotype Data Table:**- **Phenotype KB:** 27 males- **Phenotype Kb:** 213 males- **Phenotype f kB:** 33 males- **Phenotype f KB:** 354 males- **Phenotype L:** 912 males- **Phenotype l:** 948 males- **Phenotype f kb:** 177 males- **Phenotype F:** 348 males**Questions:**1. **F1 females have __________ phenotypes.**2. **Parental, non-cross over genotypes are _______ & ________.**3. **Single cross-over genotypes are _______, _______ & _______, _______.**4. **Double cross-over genotypes are _______ & ________.**5. **The gene in the middle is _______.**6. **Recombination frequencies & map distances (% or centiMorgans, cM) are:** - A. **f ↔ kb** _____ & ______ - B. **kb ↔ l** _____ & ______ - C. **l ↔ f** _____ & ______7.

Name: **Genetics Exercise: Mapping X-Linked Genes in Drosophila** **Overvie
Uploaded: 2024-03-20T06:42:55.000Z
Channel: Bartleby
Description: **Genetics Exercise: Mapping X-Linked Genes in Drosophila** **Overview:**Males of many diploid species, such as humans, have X and Y sex chromosomes. They are hemizygous for most X-linked genes, expressing X-linked alleles, whether dominant or reces

Answered: heightened responses to ethanol, and…

Human Anatomy & Physiology (11th Edition)

11th Edition

ISBN:9780134580999

Author:Elaine N. Marieb, Katja N. Hoehn

Publisher:Elaine N. Marieb, Katja N. Hoehn

Chapter1: The Human Body: An Orientation

Section: Chapter Questions

Problem 1RQ: The correct sequence of levels forming the structural hierarchy is A. (a) organ, organ system,...

See similar textbooks

Related questions

Concept explainers

Topic Video

Question

**Genetics Exercise: Mapping X-Linked Genes in Drosophila**

**Overview:**
Males of many diploid species, such as humans, have X and Y sex chromosomes. They are hemizygous for most X-linked genes, expressing X-linked alleles, whether dominant or recessive. In Drosophila (fruit fly), test crosses are used to explore X-linked genes in females. By observing male offspring's phenotypes, gene mapping is achieved, naming the gene after the mutant phenotype.

**Activity:**
Establish gene order and map distances between three X-linked genes in Drosophila:
- **fruitless (f)**: Bisexual phenotype.
- **lush (l)**: Heightened ethanol response.
- **ken&barbie (kb)**: Lacks external genitalia.

These genes are expressed as recessive mutant alleles. Flies' genotypes and phenotypes for gene mapping in this exercise are fictional.

**Experimental Design:**
1. **P1 Generation:**
- **Cross:** Homozygous F KB l / F KB l females X f kb L / Y males.
- **Result:** F1 female progeny.

2. **F2 Generation:**
- F1 females mated with males.

**Phenotype Data Table:**
- **Phenotype KB:** 27 males
- **Phenotype Kb:** 213 males
- **Phenotype f kB:** 33 males
- **Phenotype f KB:** 354 males
- **Phenotype L:** 912 males
- **Phenotype l:** 948 males
- **Phenotype f kb:** 177 males
- **Phenotype F:** 348 males

**Questions:**

1. **F1 females have __________ phenotypes.**

2. **Parental, non-cross over genotypes are _______ & ________.**

3. **Single cross-over genotypes are _______, _______ & _______, _______.**

4. **Double cross-over genotypes are _______ & ________.**

5. **The gene in the middle is _______.**

6. **Recombination frequencies & map distances (% or centiMorgans, cM) are:**
- A. **f ↔ kb** _____ & ______
- B. **kb ↔ l** _____ & ______
- C. **l ↔ f** _____ & ______

7.

Expert Solution

INTRODUCTION

The technique of pinpointing a gene's position on a chromosome is known as gene mapping. The most effective method for mapping genes nowadays includes sequencing a genome, then employing software to evaluate the data and pinpoint the locations of genes.

SIGNIFICANCE OF GENE MAPPING-
Any feature that is influenced by inheritance, including human diseases, can be powerfully identified by using genetic mapping to pinpoint the genes and biological mechanisms involved.

MECHANISM-
The idea of genetic linkage is the foundation of a genetic map: the likelihood that two markers on a chromosome will be inherited jointly increases with their proximity on the chromosome. The relative placement of genetic markers along a chromosome can be determined by examining inheritance patterns.

Step by step

Solved in 3 steps

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.

Similar questions