S138-Yamato Shiota - Intro to Genetics Study Guide

Locus

The specific location of a gene or DNA sequence on a chromosome.

Chromosome Count

The number of chromosomes varies through different stages of the human lifecycle, with gametes being haploid and somatic cells being diploid.

Heredity

The passing of traits from parents to offspring.

Asexual Reproduction

Reproduction that does not involve the fusion of gametes, producing genetically identical offspring.

Sexual Reproduction

Reproduction that involves the fusion of male and female gametes, creating genetic diversity.

Karyotype

A visual representation of an individual's complete set of chromosomes.

Sex Chromosomes

Chromosomes that determine the sex of an organism, such as X or Y in humans.

Autosomal Chromosomes

Chromosomes that are not involved in determining the sex of an organism.

Zygote

The fertilized egg that results from the fusion of gametes.

Fertilization

The process by which male and female gametes combine to form a zygote.

Alterations of Generations

A life cycle pattern that includes both a multicellular diploid form and a multicellular haploid form.

Meiosis I

The first division of meiosis that separates homologous chromosomes.

Meiosis II

The second division of meiosis that separates sister chromatids.

Mitosis

A type of cell division that results in two identical daughter cells.

Synapsis

The pairing of homologous chromosomes during meiosis, allowing for crossing over.

Haploid

A cell with a single set of unpaired chromosomes, typical of gametes.

Diploid

A cell containing two complete sets of chromosomes, one from each parent.

Somatic Cells

Any cell of a living organism other than the reproductive cells.

Gametes

Reproductive cells (sperm and eggs) that carry half the genetic information.

Independent Assortment

The principle that different genes independently separate from one another when reproductive cells develop.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis.

Random Fertilization

The random combination of sperm and egg, contributing to genetic variation.

Characters

Observable traits or characteristics of an organism.

Traits

Specific variations of a character.

Hybridization

The crossing of two different true-breeding varieties.

True-Breeding

Organisms that consistently produce offspring identical to themselves for a specific trait.

Dominant Alleles

Alleles that express their trait even when paired with a different allele.

Recessive Alleles

Alleles that express their trait only when paired with another recessive allele.

Genotypes

The genetic makeup of an organism.

Phenotypes

The physical expression of a genotype.

Law of Segregation

The principle stating that allele pairs separate during gamete formation.

Law of Independent Assortment

The principle stating that alleles for different traits are distributed to gametes independently.

Punnett Square

A grid used to predict the genetic outcomes of a cross.

Test Cross

A cross between an individual with an unknown genotype and a homozygous recessive individual.

Complete Dominance

A form of dominance where the dominant allele completely masks the effect of the recessive allele.

Incomplete Dominance

A form of inheritance where the phenotype is a blend of the two parental traits.

Codominance

A form of inheritance where both alleles are fully expressed in the phenotype.

Pleiotropy

The ability of one gene to affect multiple phenotypic traits.

Epistasis

A genetic interaction where one gene affects the expression of another gene.

Qualitative Traits

Traits that are expressed in categorical terms.

Quantitative Traits

Traits that vary in degree and can be measured.

Nature vs. Nurture

The debate regarding the relative contributions of genetic inheritance and environmental factors to human development.

Pedigrees

Family trees used to analyze the inheritance of traits.

Recessive Disorders

Genetic disorders that manifest only in individuals who inherit two recessive alleles.

Dominant Disorders

Genetic disorders that manifest in individuals who inherit at least one dominant allele.

Carriers

Individuals who carry one copy of a recessive allele but do not express the trait.

Wildtype

The most common phenotype or genotype in a population.

Sex-Linked Genes

Genes that are located on the sex chromosomes.

X-Linked Genes

Genes that are located specifically on the X chromosome.

Karyotypes Arrangement

Chromosomes arranged by size and shape for analysis.

Genomic Imprinting

The phenomenon where certain genes are expressed in a parent-of-origin-specific manner.

Genetic Map

A representation of the arrangement of genes on a chromosome.

Linkage Map

A map showing the relative positions of genes on a chromosome based on recombination frequencies.

Nondisjunction

The failure of chromosomes to separate properly during cell division.

Aneuploidy

An abnormal number of chromosomes in a cell.

Monosomic

A condition where there is one less than the usual number of chromosomes.

Trisomic

A condition where there is one extra chromosome.

Polyploidy

The condition of having more than two complete sets of chromosomes.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis.

Genetic Recombination

The production of offspring with combinations of traits that differ from those found in either parent.