The promoter or enhancer segments of all genes regulated by PKA contain a cis-acting DNA sequence, the cAMP-response element (CRE), which

contains the highly conserved nucleotide sequence,

5'-TGACGTCA-3'.

TLS Online TPP Program

#Id: 3695

#Unit 2. Cellular Organization

The Y chromosome has 60 genes that are expressed specifically in the testis.

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#Id: 3696

#Unit 2. Cellular Organization

Not all genes are essential. In yeast and flies, deletions of 50% of the genes have detectable effects

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#Id: 3697

#Unit 2. Cellular Organization

Most known genetic defects in human genes are due to point mutations. The majority directly affect the protein sequence

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#Id: 3698

#Unit 2. Cellular Organization

Deletion appears to have no effect when genes are present in multiple copies called as gene redundancy

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#Unit 2. Cellular Organization

Genetic redundancy means that two or more genes are performing the same function and that inactivation of one of these genes has little or no effect on the biological phenotype

Redundancy seems to be widespread in genomes of higher organisms

TLS Online TPP Program

#Id: 3700

#Unit 2. Cellular Organization

Deletions in two genes, neither of which is lethal by itself, are introduced into the same strain. If the double mutant dies, the strain is called a synthetic lethal. This technique has been used to great effect with yeast, where the isolation of double mutants can be automated. The procedure is called synthetic genetic array analysis (SGA)