CHAPTER 4 GENETICS, EVOLUTION, DEVELOPMENT, AND PLASTICITY

Mendelian Genetics

The principles of heredity formulated by Gregor Mendel, demonstrating how traits are inherited through genes.

Gene

Units of heredity that maintain their identity from one generation to the next and are segments of DNA.

Chromosomes

Strands of genes that contain genetic information inherited from parents.

Deoxyribonucleic Acid (DNA)

A double-stranded chemical that makes up chromosomes and carries genetic instructions.

Ribonucleic Acid (RNA)

A single-stranded chemical that serves as a template for protein synthesis.

Enzymes

Biological catalysts that regulate chemical reactions in the body.

Homozygous

Having an identical pair of genes for a particular trait.

Heterozygous

Having an unmatched pair of genes for a particular trait.

Dominant Gene

A gene that shows its effects in both homozygous and heterozygous conditions.

Recessive Gene

A gene that only shows its effects in homozygous conditions.

Heritability

The extent to which variation in a characteristic can be attributed to genetic differences.

Phenylketonuria (PKU)

A genetic disorder that results in a failure to metabolize phenylalanine, requiring environmental intervention to manage.

Evolution

Change in gene frequencies within a population over generations.

Natural Selection

The process through which traits that enhance survival and reproduction become more common in a population.

Neural Darwinism

The principle that synapses form randomly, followed by a selection process that retains some and eliminates others.

Apoptosis

Programmed cell death that occurs when a neuron does not make the right synaptic connection.

Fetal Alcohol Syndrome (FAS)

A condition arising from alcohol consumption during pregnancy, leading to developmental issues in the fetus.

Dendritic Branching

The growth of neural connections resulting from environmental enrichment and experience.

Phantom Limb

The sensation that an amputated body part is still present, linked to reorganization in the somatosensory cortex.

Denervation Supersensitivity

Increased responsiveness of remaining synapses following the inactivity of a certain set of synapses.

Alleles

Different versions of a gene that may produce distinguishable traits.

Genotype

The genetic makeup of an individual, represented by the alleles they possess.

Phenotype

The observable traits or characteristics of an individual, influenced by their genotype.

Punnett Square

A diagram used to predict the genetic outcomes of a cross between two organisms.

Genetic Drift

Random changes in allele frequencies in a population, often occurring in small populations.

Mitosis

The process of cell division that results in two identical daughter cells, maintaining the same chromosome number.

Meiosis

The process of cell division that produces gametes, resulting in half the chromosome number of the parent cell.

Codominance

A genetic scenario where both alleles in a heterozygote are fully expressed.

Incomplete Dominance

A genetic scenario where the phenotype of heterozygotes is intermediate between the two homozygotes.

Chromatid

One of two identical halves of a replicated chromosome.