Genetics

links: reference:

• [Lysenko and Russian genetics: an alternative view]
• https://yewtu.be/channel/UCgppXxw5o8SpghtVSj8tX-A/videos 6-12-2021

Genetics #

Book Notes #

• Genomics is the study of complete DNA sequences of a species or an individual.
• Variable messages transcribed from the same gene are called splice variants.
• Regulatory DNA sequences (promoters and introns) that control whether and in what quantities a gene iss expressed in a given cell type.
• Chromosones (generally?) get progressively shorter from 1->22.
• Transcription: Copying a segment of DNA -> RNA -> mRNA. This takes place in the nucleus.
  • RNA polymerase converts the gene into pre-mRNA (aka primary transcript mRNA), which contains introns, which are then removed during RNA splicing, leaving mature mRNA.
• Translation: In the ribosome, mature mRNA provides a template while tRNA (transfer RNA) carries and supplies the amino acids, eventualy producing a polypeptide.
• Codon: Basic unit of 3 nucleotides, which form an amino acid - or signals a stop:
  • As you can see, Methionine is always the only start codon (for archaea). And therefore, always AUG?
  • “Degeneracy” refers to the fact that the amino acids besides methionine and tryptophan have >1 codon.
• Gene: a stretch of DNA that encodes for a… product. Not all transcripts are mRNA (it can also be rRNA or tRNA) so it wouldn’t be accurate to say otherwise.
  • Promoters are where RNA polymerase binds.
  • Enhancer somehow enhance binding of transcriptional machinery.
  • Silencers (operators in prokaryotes) bind transcription factors or something.
  • There’s something like 37,000 genes in the human genome.
• Intron: A region in a gene that is removed during mRNA processing beforew transcription; this is as opposed to an exon.
• Incomplete dominance is when two alleles mix. For instance: A/A = red, a/a = white, and A/a = pink. Unlike eye colors.
• Co-dominance is expressing the phenotype of both alleles simultaneously. For example, having the blood type AB = both A and B antigens.

Karyotype/Chromosome physiology #

• Centromeres are where microtubules bind on the chromosome: . DNA Sequencing returns blank/filler characters where the centromere is.
• The banding is known as Giesma/G-banding. AT/GC ratio is relevant, since GC-rich domains indicates density of genes and open chromatin (euchromatin) (higher transcriptional activity), and this = light bands.
• Chromosomal locations of a gene follows this notation: