epigenetics

genome

genome refers to all genetic material present, including genes and non—coding DNA.

gene expression

The process of copying information from DNA onto mRNA and translating the message into a series of amino acids.

transcription

DNA is copied by mRNA inside nuclues

stages of transcription

1.       A gene is a specific sequence of bases on the DNA molecule.

2. The DNA strands separate.

3. RNA polymerase binds to the DNA and begins transcription.

4. It adds complementary RNA nucleotides to the template strand.

5. The newly made mRNA is a copy of the coding strand but uses uracil (U) instead of thymine (T).

6. mRNA exits the nucleus through a nuclear pore and enters the cytoplasm.

translation

produce of a protein using the coded instructions in the mRNA molecule.

stages of translation

1.     attaches to a ribosome, which reads it in triplet bases called codons, starting with the start codon AUG (methionine).

2.     Transfer RNA (tRNA) brings amino acids to the ribosome, where its anticodon matches an mRNA codon, helping assemble amino acids in the correct order to form a protein.

3.     As amino acids are added, peptide bonds form between them, and this process continues until the ribosome reaches a stop codon (UAA, UAG, or UGA).

4.     Completion: the growing peptide chain is released & broken down

Histones

histones are proteins the DNA wraps around to form chromatin they help package DNA tightly in the nucleus and play a role gene regulation

Epigenetics

Epigenetics changes gene activity without changing DNA sequence.

Description of epigenetics

-        influenced by environmental factors such as diet, stress, toxins and UV light/ radiation these factors affect when, where and how much a gene is expressed.

-        Epigenetic changes n be reversible, but some may be passed on to daughter cells during cell division or even inherited by offspring  

-        Abnormal epigenetic changes are linked to diseases like cancer, diabetes and mental health disorders

what is acetylation

Acetylation adds a group to histones, loosening DNA and increasing gene expression.

what is methylation

Methylation adds a tag to cytosine, tightening DNA and decreasing gene expression.

causes of epigenetic effects

Toxins: Chemicals like cigarette smoke or pollution can cause epigenetic changes that increase disease risk and may be passed to the next generation.

causes of epigenetic effects 2

exposure to UV radiation can cause DNA damage and trigger epigenetic changes that affect gene expression which may be passed to offspring

dutch famine

-        From 1944-45

-        People survived on as little as 400-800 calories a day especially during the winter months

-        Children who were in the womb during the famine were studied decades later

-        Scientists discovered epigenetic changes in specific genes (IGF2) which plays a key role in growth and deployment

-        Individuals who were exposed to famine in the womb had less methylation on the IGF2 gene 60 years later compared to their unexposed siblings

-        The children had higher rates of metabolic disorders, diabetes, heart disease, obesity & mental health issues

-        Grandchildren of those women also showed a higher risk of health issues

-         This shows how environmental factors such as trauma, famine, stress altering how the gene is expression without changing the genetic sequence

smerican journal of clinical nutrition

-        A key gene affected is the (LEP gene) which codes for leptin a hormone that regulates appetite and energy balance

-        The breastfed infants have lower methylation levels at the (LEP gene) compared to formula fed infants

-        Lower methylation leads to higher leptin production which helps infants regulate hunger and maintain healthy body weight

-        This epigenetic change is important because it may reduce the risk of obesity and metabolic diseases later in life

-        Formula fed infants tend to have higher (LEP GENE) methylation which might increase susceptibility to weight related health issues such as obesity

-        Breastfeeding induced epigenetic modifications show how early nutrition can cause lasting changes in gene expression without altering the DNA sequence

-        These changes support the role of environmental factors like diet in shaping long term health through epigenetics