Genetics and Mendelian Inheritance

Genetics

• Genetics is the study of heredity and the variation of inherited characteristics.
• It explores how traits are passed down from parents to offspring.
• Genes, segments of DNA, are fundamental units of heredity.
• Genes determine specific traits an organism expresses.

Mendelian Inheritance

• Gregor Mendel's experiments with pea plants laid the foundation of modern genetics.
• Mendel's laws describe the pattern of inheritance of traits.
  • Law of Segregation: Each individual has two alleles for each gene, which separate during gamete formation.
  • Law of Independent Assortment: Genes for different traits segregate independently during gamete formation.
• Dominant and recessive alleles determine how traits are expressed.
• Homozygous individuals carry two identical alleles, while heterozygous individuals carry two different alleles.
• Phenotype refers to the observable characteristic resulting from gene expression.
• Genotype refers to the genetic makeup (allele combinations).

Genetic Variation

• Genetic variation arises from differences in the genetic material of organisms.
• Sources of variation include:
  • Mutations: Changes in the DNA sequence
  • Recombination during meiosis: Mixing of genetic material.
  • Gene flow: Migration and interbreeding between populations.
  • Genetic drift: Random changes in allele frequencies.
• Genetic variation is crucial for adaptation and evolution.
• Natural selection favors traits that enhance survival and reproduction in particular environments.

DNA Structure and Function

• DNA is a double helix composed of nucleotides.
• Nucleotides consist of a sugar (deoxyribose), a phosphate group, and a nitrogenous base (adenine, guanine, cytosine, or thymine).
• Adenine pairs with thymine, and guanine pairs with cytosine.
• Double helix structure provides stability and allows for DNA replication.
• DNA carries genetic information.
• It specifies the sequence of amino acids in proteins.
• DNA replication is a crucial process for cell division.
• DNA is transcribed into RNA, which is translated into proteins.
• DNA is the fundamental molecule of heredity in most organisms.
• The sequence of bases in DNA determines the code and instructions for the synthesis of specific proteins.
• The process of transcription converts DNA information into RNA, and translation then converts RNA information into proteins.
• DNA structure is crucial to its function in storing and transmitting genetic information.