Linked Genes

Objectives:

Relate genes, traits, chromosomes, and DNA.

Contrast gene linkage with Mendelian inheritance.

Define recombination and mapping.

Distinguish between autosomes and sex chromosomes.

Compare and contrast sex-linked, sex-limited, and sex-influenced traits.

Web Resources:

http://www.biology.arizona.edu/mendelian_genetics/mendelian_
http://biology.clc.uc.edu/courses/bio105/sex-link.htm

Notes:

 Linked genes are located in the same chromosome and do not sort independently.

 Chromosomes sometimes cross over during meiosis, resulting in recombination of alleles.

 Sex chromosomes determine the sex of offspring. All other chromosomes are autosomes.

 The human sex chromosomes are the X chromosome and the Y chromosome.

 Genes located on sex chromosomes are sex-linked genes.

 Sex-limited and sex-influenced traits are controlled by genes located on autosomes, but

these traits are affected by sex hormones.

Words to Know

linked genes         crossing over        autosomes         sex chromosomes         sex-linked genes

sex-limited traits         sex-influenced traits