BIO 120 Final Exam Review: Genetics, Biotechnology, and Patterns of Inheritance

Biotechnology

Introduction to Biotechnology

Biotechnology involves the use of living organisms or their components to develop products or processes for specific use. It is a rapidly advancing field with applications in medicine, agriculture, and environmental science.

• Genetic Engineering: The direct manipulation of an organism's genes using biotechnology techniques.

• Polymerase Chain Reaction (PCR): A technique used to amplify small segments of DNA, making millions of copies for analysis.

• Gel Electrophoresis: A method for separating DNA fragments based on their size using an electric field.

• Cloning: The process of creating genetically identical copies of DNA, cells, or organisms.

• DNA Sequencing: Determining the precise order of nucleotides within a DNA molecule.

• Plasmid: Small, circular DNA molecules found in bacteria, often used as vectors in genetic engineering.

• Restriction Fragment: DNA fragments produced by the action of restriction enzymes, which cut DNA at specific sequences.

• Recombinant DNA: DNA molecules formed by laboratory methods of genetic recombination to bring together genetic material from multiple sources.

• Gene Therapy: The introduction, removal, or alteration of genetic material within a person's cells to treat disease.

Example: Insulin production using genetically modified bacteria is a classic application of biotechnology.

Patterns of Inheritance

Basic Principles

Patterns of inheritance describe how traits and genetic information are passed from one generation to the next. Mendelian genetics forms the foundation of this field.

• Autosome: Any chromosome that is not a sex chromosome.

• Sex Chromosome: Chromosomes involved in determining the sex of an organism (e.g., X and Y in humans).

• Dominant and Recessive: Dominant alleles mask the effect of recessive alleles in heterozygotes.

• Codominance: Both alleles are fully expressed in the phenotype of heterozygotes (e.g., AB blood type).

• Incomplete Dominance: The phenotype is a blend of both alleles (e.g., red and white flowers producing pink offspring).

• Multiple Alleles: More than two possible alleles exist for a gene (e.g., ABO blood group).

• Epistasis: One gene affects the expression of another gene.

• Pleiotropy: One gene influences multiple phenotypic traits.

• Polygenic Inheritance: Multiple genes contribute to a single trait (e.g., skin color).

• Pedigree: A diagram showing the inheritance of a trait over several generations.

Example: Sickle cell anemia is inherited in an autosomal recessive pattern.

Human Genetics

Genetic Disorders and Inheritance

Human genetics studies the inheritance of traits and disorders in humans, including the analysis of pedigrees and chromosomal abnormalities.

• Carrier: An individual who has one copy of a recessive allele that causes disease in the homozygous state.

• Genetic Counseling: Advising individuals and families about the risks of genetic disorders.

• Amniocentesis: A prenatal test in which a small amount of amniotic fluid is sampled to detect chromosomal abnormalities.

• Chorionic Villus Sampling (CVS): A prenatal test involving the sampling of placental tissue to diagnose genetic disorders.

• Nondisjunction: The failure of chromosomes to separate properly during meiosis, leading to aneuploidy (e.g., Down syndrome).

• Sex-linked Inheritance: Traits controlled by genes located on sex chromosomes, often X-linked (e.g., hemophilia).

• Autosomal Dominant/Recessive: Inheritance patterns for genes located on autosomes.

Example: Cystic fibrosis is an autosomal recessive disorder, while Huntington's disease is autosomal dominant.

Genetic Mapping and Linkage

Understanding Gene Location and Inheritance Patterns

Genetic mapping involves determining the relative positions of genes on a chromosome and how they are inherited together.

• Linkage: Genes located close together on the same chromosome tend to be inherited together.

• Crossing Over: The exchange of genetic material between homologous chromosomes during meiosis, leading to genetic recombination.

• Recombination Frequency: Used to estimate the distance between genes on a chromosome.

• Map Unit (centimorgan): A unit of measurement for genetic linkage; 1% recombination frequency equals 1 map unit.

Example: If two genes have a recombination frequency of 10%, they are 10 map units apart.

Table: Key Terms in Genetics and Biotechnology

Term	Definition
Autosome	Any chromosome not involved in sex determination
Plasmid	Small, circular DNA molecule used as a vector in genetic engineering
Carrier	Individual who carries one copy of a recessive allele for a genetic disorder
Codominance	Both alleles are fully expressed in the phenotype
Gene Therapy	Treatment involving the introduction or alteration of genes in a patient
Nondisjunction	Failure of chromosomes to separate properly during meiosis

Additional info: This review covers core concepts from chapters on inheritance, genetics, and biotechnology, including Mendelian and non-Mendelian inheritance, genetic mapping, and modern genetic technologies.