Evolution and Mutations in Life Forms

Study Notes

The earliest living organism was a single-celled organism that reproduced asexually.
All life on Earth today can be traced back to this common ancestor, called the Last Universal Common Ancestor (LUCA).
Organisms have evolved over billions of years, with major evolutionary developments such as multicellularity, photosynthesis, and respiration.

Mutations are a change in the DNA sequence.
Most mutations occur in somatic cells and are not passed on to future generations.
Mutations in gametes (sperm or egg cells) are passed on to offspring, impacting future generations.
Mutations can arise from various sources, such as exposure to UV radiation, which can cause thymine base crosslinking.
Some mutations can lead to diseases like xeroderma pigmentosum, which is an autosomal recessive disorder that affects DNA repair mechanisms.

Chromosomal mutations involve changes in the structure or number of chromosomes.
Translocations occur when two non-homologous chromosomes exchange genetic material, creating derivative chromosomes.
Translocations can cause infertility or lead to cancer development.

A force of evolution that involves random changes in allele frequencies from one generation to the next.

Autosomal dominant genetic disorder that affects the neurofibromin protein, a protein involved in many biochemical pathways.
Symptoms of NF1 can include skin, neurological, and skeletal abnormalities.
The NF1 gene is large, increasing its susceptibility to mutations.
The mutability of NF1 may offer some benefits, though this requires further investigation.

Autosomal recessive disorder that affects millions worldwide.
Most common in Africa, the Mediterranean, and India.
Sickle cell anemia is characterized by altered hemoglobin, leading to sickle-shaped red blood cells.
The sickle cell trait can confer resistance to malaria in heterozygotes.