W1 L1 what is a gene

Question 1

What is a gene according to past scientist

Answer 1

• According to Gregor Mendel, a gene is a unit of inheritance, transmitted between generations
• Watson & Crick, an expressed region of DNA, encoding a functional protein
• Our Sanger, an annotated open reading frame, predicted from DNA sequence

Question 2

Current definition of gene

Answer 2

A gene is a:
-heritable unit of DNA with specific features and regulatory elements that permit its transcription into an RNA sequence through spatial and temporal control mechanisms.
- Gene transcripts possess sequences that act as instructions for transcript modification to generate the final functional structure which can be in the form of RNA or protein. This is achieved via the interaction with other gene products and various environmental factors in a complex dynamic regulatory network.

Question 3

Human gene number

Answer 3

20k gene
The human genome consists of 53% repetitive DNA and 47% unique sequences.

Question 4

ENCODE: Encyclopedia of DNA Elements:

Answer 4

• Map all of the functional elements of the human genome
• Functionally defines as:
  − Transcriptionally active regions (TARs) of the genome
  − Regions bound by proteins regulating transcription
  − Architecture (location and sequence) of gene regulatory elements
  − Assort some sort of function to 80% of the genome, 70k promoter regions & 400k enhancer regions

Question 5

experiments done to assess the functionality of DNA sequences

Answer 5

• DNA methylation, chromatin state, binding and association with transcription factors in a method called Chip-seqand histone modifications
• This is being assessed in different cell types and tissues, with 3 categories of most commonly used cells types

Question 6

What has encode found

Answer 6

− Widespread transcription of non-genic DNA can undergo splicing
− More alternative splicing than previously detected
− Many transcripts span multiple gene loci, gene extend into other intergenic regions
− large number of unannotated transcriptional start sites
− dispersed regulation is common for many genes. Regulatory elements can be upstream, downstream, in genes or very far away
− more transcriptional complexity

Question 7

gene definition after encode

Answer 7

The gene is a union of genomic sequences encoding a coherent set of potentially overlapping functional products