Understanding Traits, Genes, and Mutations

Classified in Biology

Written at February 12, 2025 on English with a size of 3.12 KB.

Traits are characteristics present in an organism that can be inherited by its offspring.

Understanding the relationship between the inheritance of traits and the transfer of DNA in reproduction processes leads us to genes.

A gene is a section of DNA that contains information about a certain trait and controls that trait. Alleles are the different alternatives for a gene controlling a particular trait.

Alleles: A gene is found in a specific position, or locus, on a specific type of chromosome. There are two alleles for each gene.

Homozygotes and Heterozygotes

Two identical alleles (AA or aa): Homozygous
Two different alleles (Aa): Heterozygous

A: Dominant allele

a: Recessive allele

Genotype is an organism's set of genes.

Phenotype is the way in which a genotype is expressed in specific environmental conditions.

Mutations

Mutations are changes in the DNA sequence of a cell that are transferred to other cells resulting from it. Most mutations occur naturally as spontaneous mutations. Mutations can also be induced by mutagenic agents, such as X-rays and ultraviolet radiation.

Mutations are the main way genetic information is modified, leading to different organisms and biodiversity.

Types of Mutations

According to the Effect:

Harmful: Affects basic structures and can cause death.
Beneficial: Benefits an individual's survival, contributing to the genetic variability of a population.
Neutral: Does not affect survival.

According to the Cells They Affect:

Germline: Affects germ cells that originate in the sex cells and are passed to offspring.
Somatic: Affects somatic cells. When the cells multiply, all the resulting cells carry the mutation, but the mutation is not passed to the offspring.

According to the Size of the Mutation:

Gene mutations: Changes in the sequence of nucleotides in a specific gene.
Chromosomal mutations: Changes in the structure of a chromosome.
Genomic mutations: Changes in the individual's chromosome count. Types:
- Aneuploidy: An extra chromosome (trisomy) or one chromosome less (monosomy).
- Euploidy: The number of haploid sets is different from normal. Two types:
  - Polyploidy mutations: 3n or 4n sets appear instead of 2n.
  - Monoploidy mutations: Only one set of chromosomes (n).

Genetic disorders are alterations to an individual's health caused by the defective functioning of a certain gene.

Cell division is a process in which two daughter cells that contain the same information as the parent cell are created.

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