Z disk 

Thin actin filaments are assembled with their (+) ends embedded in a densely staining structure

TLS Online TPP Program

#Id: 8962

#Section 3: Genetics, Cellular and Molecular Biology

Fate of duplicate gene 

TLS Online TPP Program

#Id: 8963

#Section 3: Genetics, Cellular and Molecular Biology

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.

TLS Online TPP Program

#Id: 8964

#Section 3: Genetics, Cellular and Molecular Biology

A third fate that can befall a duplicated gene is neofunctionalization. Here the duplicate evolves a novel biological function. 

TLS Online TPP Program

#Id: 8960

#Section 3: Genetics, Cellular and Molecular Biology

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: 2243

#Section 3: Genetics, Cellular and Molecular Biology

The loci that encode hemoglobins are members of a gene family, which is a set of loci that arose by duplication.

TLS Online TPP Program

#Id: 8966

#Section 3: Genetics, Cellular and Molecular Biology

Molecular Variation (Rate) - Which is the number of substitutions taking place per nucleotide site per year