Instead, a dedicated protein (a special elongation factor) named SELB in complex with GTP is required to deliver Sec–tRNASec to the ribosome.

TLS Online TPP Program

#Id: 8958

#Unit 11. Evolution and Behavior

Genetic exchange also happens between distantly related organisms by horizontal gene transfer, or HGT.

HGT is particularly important to prokarytotes and is the most common way by which they acquire new genes.

TLS Online TPP Program

#Id: 8959

#Unit 11. Evolution and Behavior

Intimacy between the genomes of the mitochondria and the nucleus within a cell, it may not be surprising that extensive HGT has occurred between them

TLS Online TPP Program

#Id: 8960

#Unit 11. Evolution and Behavior

Duplicate gene and its parental copy can subfunctionalize so that each carries out only some of the roles that the ancestral gene performed. 

Ex- a duplicate of the β-hemoglobin locus is expressed in the fetus. 

TLS Online TPP Program

#Id: 8961

#Unit 11. Evolution and Behavior

No matter how it is born, a new gene starts its life as a single copy in the population.

As with any new mutation, by far the most likely outcome is that it will be lost by random drift or selection over the next few generations

TLS Online TPP Program

#Id: 8962

#Unit 11. Evolution and Behavior

Fate of duplicate gene 

TLS Online TPP Program

#Id: 8963

#Unit 11. Evolution and Behavior

If the duplicate is redundant and does not provide a fitness benefit, it will be lost by deletion or the accumulation of loss of-function mutations.

A second fate is that a duplicate can simply retain its original function.