Human Genetics 10th Edition

Genetics Overview

• Genetics is the study of inherited traits and their variation
• It is a life science that should not be confused with genealogy
• Genetics is also an informational science that has a huge societal impact

Genes

• Contain instructions within cells for protein production
• Composed of deoxyribonucleic acid (DNA)
• Traits are produced by an interaction between genes and their environment

Genome

• The complete set of genetic information for an organism
• Includes all genes present in an organism and DNA sequences that do not encode genes
• Genomics is a field that analyzes and compares genomes of different species

Levels of Genetics

• There are multiple levels of genetics, which will be discussed further in the text

DNA (Deoxyribonucleic Acid)

• A double-stranded polymer consisting of a chain of nucleotides
• Deoxyribonucleotide components: phosphate, sugar (deoxyribose), and base (adenine, guanine, thymine, and cytosine)
• The sequence of bases codes for the amino acid sequence in a protein

RNA (Ribonucleic Acid)

• A single-stranded polymer of ribonucleotides
• Ribonucleotide components: phosphate, sugar (ribose), and base (adenine, guanine, uracil, and cytosine)
• Exists in several types and uses information from DNA to construct proteins

Genes and Chromosomes

• Alleles are variants of genes that form by mutation
• Mutations in sperm or egg cells are passed on to the next generation
• Chromosomes are composed of DNA and protein and are found in the nucleus of the cell
• Human somatic cells have 46 chromosomes (22 pairs of autosomes and a pair of sex chromosomes)

Genome Organization

• A karyotype is a chart displaying the chromosome pairs from largest to smallest
• A human body contains approximately 50-100 trillion cells, all of which (except RBCs) contain the same genome
• Differentiation causes cells to differ in appearance and function, controlled by variation in gene expression
• Stem cells are less specialized and can become many different cell types

Biological Organization

• Levels of biological organization include cells, tissues, organs, organ systems, and organisms

Individuals and Families

• The genotype of an individual refers to the alleles they carry
• The phenotype is the visible trait
• A dominant allele is expressed if the individual carries just one copy
• A recessive allele is only expressed if the individual carries two copies
• A pedigree is a diagram used to study traits in families

Mendelian vs. Multifactorial Traits

• Mendelian traits are determined by a single gene and have predictable inheritance patterns
• Multifactorial traits are determined by one or more genes and the environment and have complex inheritance patterns
• Most traits are multifactorial

Applications of Genetics

• Genetics has many applications, including DNA profiling (forensics, history, and ancestry), health care (pharmacogenomics, personalized medicine), agriculture (traditional breeding and biotechnology), and ecology (metagenomics, environmental monitoring)

This quiz covers the concepts and applications of human genetics, including the study of inherited traits and their variation. It is based on the 10th edition of the book by Ricki Lewis.