6.The gene map produced on based on recombination frequency data are termed as
(1) Deletion map               (2) Linkage map
(3) Physical map              (4) Cytogenetic

Introduction:
Gene mapping is a crucial tool in genetics for understanding the arrangement and inheritance of genes along chromosomes. Among various types of gene maps, the linkage map—based on recombination frequency data—is fundamental for illustrating relative gene positions. This article explains the different types of gene maps, focusing on the linkage map derived from recombination frequencies, clarifying its definition, purpose, and the distinctions from other map types.

Explanation of Each Option:

1. Linkage Map:
   A linkage map is a genetic map that shows the relative positions of genes or genetic markers on a chromosome based on recombination frequencies during meiosis. The recombination frequency between two genes reflects how often crossing over occurs between them; a lower frequency means the genes are close together, while a higher frequency indicates they are farther apart. Linkage maps do not indicate exact physical distances but rather the relative distances, often measured in centimorgans (cM). This map type was first developed by Alfred Sturtevant and remains essential for mapping gene order and linkage groups in organisms.​

2. Deletion Map:
   A deletion map shows the location of genes based on known chromosomal deletions. It identifies missing segments of chromosomes to infer gene positions by determining which genes are absent in deletion mutants. This map helps locate genes relative to chromosomal deletions but is different from the recombination frequency-based linkage map [general genetics knowledge].

3. Physical Map:
   A physical map represents the actual physical distances between genes or markers on the DNA molecule, measured in base pairs or kilobases. It involves direct measurement techniques such as restriction mapping, fluorescence in situ hybridization (FISH), or sequencing. Physical maps provide precise gene locations rather than relative positions based on genetic recombination [general genetics knowledge].

4. Cytogenetic Map:
   A cytogenetic map shows gene locations based on visible features on stained chromosomes under a microscope, such as banding patterns. This map type links genetic information to chromosomal morphology and is useful for associating specific genes with certain chromosome regions [general genetics knowledge].

Answer:
The gene map produced based on recombination frequency data is termed a linkage map. It shows the relative positions of genes on chromosomes by measuring how often genetic recombination occurs between them during meiosis. This differentiates it from deletion maps (based on chromosomal deletions), physical maps (based on actual distances in DNA), and cytogenetic maps (based on chromosomal staining patterns). Thus, the correct answer is (2) Linkage map.​

This explanation highlights the key differences between map types and focuses on the importance of the linkage map in genetic analysis, especially regarding recombination frequencies, addressing the question thoroughly and optimally for SEO.