Autosomal linkage

Question 1

What are autosomes?

Answer 1

• are chromosomes which are not concerned with sex determination

Question 2

How are autosomes different to chromosomes?

Answer 2

• they are entirely homologous
• have two copies each gene
• one on each member of the pair

Question 3

What are linked genes?

Answer 3

• any genes which are located on the same chromosome

Question 4

What is autosomal linkage?

Answer 4

• if two or more genes are located on the same automsomes (non-sex chromosomes)

Question 5

Summary

Answer 5

• Genes are found on separate chromsomes are unlinked
• Unlinked genes undergo independent assortment during meiosis
• this results in equal proportions of recombinant and non-recombinant gametes
• genes that are on the same autosome are autosomally linked
• the alleles of linked genes stay together during independent assortment unless crossing over occurs
• crossing over is random
• this means, if the genes are linked, there are more likely to be higher proportions of gametes with the same allele combination as the parent cells and fewer recombinants
• the closer together the two genes are on the chromsomes the less likely crossing over is likely to occur - this is called tight linkage.
• the tighter the linkage the fewer recombinants gametes are produced