Human Genes and Genomes: Chapter Summaries

Genetics

The science of heredity and inherited variation, focusing on biological information necessary for growth, development, reproduction, and death.

Chromosome

Cellular structures where genetic information is packaged, forming a genome, with humans having 23 pairs (46 total) in diploid cells.

Gene

Units of inheritance composed of DNA, storing information in a unique sequence of nucleotides, forming the basis of traits transmission.

Mutation

Heritable changes in DNA sequence or arrangement, occurring at genome, chromosome, or gene levels, affecting protein function and regulatory processes.

DNA

Deoxyribonucleic acid, carrying genes and forming chromosomes, with mutations being essential for evolution and individual genetic differences.

Genome

The sum total of genes and chromosomes in a cell, with the human nuclear genome consisting of 24 distinct chromosomes and about 21,000 genes.

Genomics

The study of whole genomes, enabled by DNA sequencing, revealing variations like single nucleotide polymorphisms (SNPs) and copy number variations (CNVs).

Natural Selection

The process by which genotypes best suited for survival and reproduction in an environment increase in frequency in a population over generations.

Karyotype

Visualization of chromosomes in homologous pairs according to size and centromere position, used to detect abnormalities like aneuploidy.

Single-Gene Mutation

Mutations affecting a single gene, with significant effects on child health, elucidating biochemical pathways and aiding in diagnostic and therapeutic strategies.

Multifactorial traits

Traits influenced by multiple genetic and environmental factors, not following Mendelian inheritance patterns.

Quantitative traits

Traits like height that vary continuously and follow a normal distribution curve.

Qualitative traits

Traits like cleft lip or schizophrenia with distinct classes of affected and unaffected individuals.

Candidate gene studies

Research seeking mutations in genes relevant to a trait to understand genetic contributions.

Genome-wide association studies

Studies comparing single nucleotide polymorphism frequencies in individuals with a trait to controls.

Hardy-Weinberg equilibrium

Principle stating allele and genotype frequencies remain constant in large, randomly mating populations.

Population genetics

Study of genetic variation distribution in populations and how genotypes, alleles, and phenotypes change or remain stable.

Molecular evolution

Field focusing on how genomes, genes, and proteins help explain species evolution, using techniques like DNA sequencing and molecular clocks.