S138-Yamato Shiota - Intro to Genetics Study Guide

What is genetics?

The study of heredity and the variation of inherited characteristics.

What are genes?

Units of heredity made up of DNA that determine specific traits.

What is a chromosome?

A long strand of DNA wrapped around proteins, containing many genes.

How many chromosomes do humans have?

Humans typically have 46 chromosomes, arranged in 23 pairs.

What is the function of DNA?

To store and transmit genetic information.

What is an allele?

A variant form of a gene that may produce different traits.

What is homozygous?

Having two identical alleles for a specific gene.

What is heterozygous?

Having two different alleles for a specific gene.

What is phenotype?

The observable physical or biochemical characteristics of an organism.

What is genotype?

The genetic constitution of an organism; its specific alleles.

What is a genetic mutation?

A permanent alteration in the DNA sequence that makes up a gene.

What is Mendelian inheritance?

Patterns of inheritance that follow the principles of Gregor Mendel.

What does the law of segregation state?

During gamete formation, the two alleles for a trait segregate from each other.

What does the law of independent assortment state?

Genes for different traits can segregate independently during gamete formation.

What is a Punnett square?

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

What is codominance?

When both alleles in a heterozygote are fully expressed.

What is incomplete dominance?

When the phenotype of a heterozygote is intermediate between the two homozygous phenotypes.

What is a pedigree chart?

A diagram that shows the occurrence and appearance of phenotypes across generations.

What is genetic recombination?

The process by which DNA is broken and recombined to form new combinations of alleles.

What is the purpose of genetic testing?

To identify genetic disorders and assess risks of inheritance.

What is gene therapy?

A technique that modifies genes to treat or prevent disease.

What are transposons?

Sequences of DNA that can move around to different positions within the genome.

What is epigenetics?

The study of changes in gene expression that do not involve changes to the underlying DNA sequence.

What is polygenic inheritance?

Inheritance pattern of traits that are controlled by multiple genes.

What are sex-linked traits?

Traits associated with genes located on sex chromosomes, often on the X chromosome.

What is a karyotype?

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

What is a carrier?

An individual who has one copy of a recessive allele for a trait but does not exhibit the trait.

What is genetic drift?

A change in allele frequencies in a population due to random sampling.

What is natural selection?

The process through which individuals with favorable traits are more likely to reproduce.

What is a linkage group?

A group of genes that tend to be inherited together because they are located close to each other on a chromosome.

What is the purpose of the Human Genome Project?

To map and understand all the genes of the human species.

What is a cloning vector?

A small piece of DNA that can be manipulated to insert foreign DNA into a host cell.

What is recombinant DNA?

DNA that has been artificially formed by combining constituents from different organisms.

What is phenotypic plasticity?

The ability of an organism to change its phenotype in response to environmental conditions.

What is a loci?

The specific physical location of a gene on a chromosome.

What is a squashed embryo?

An embryo that has undergone abnormal genetic development.

What is a test cross?

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

What is a dominant allele?

An allele that expresses its phenotype even in the presence of a recessive allele.

What is a recessive allele?

An allele that expresses its phenotype only when two copies are present.

What is a quantitative trait?

A trait controlled by multiple genes that show a continuous distribution of phenotypes.

What are somatic mutations?

Mutations that occur in non-germline tissues and are not passed to offspring.

What is a germline mutation?

A mutation that occurs in the reproductive cells and can be passed to the next generation.

What is molecular genetics?

The branch of genetics that deals with the structure and function of genes at a molecular level.

What is the role of histones?

Protein molecules around which DNA is tightly coiled in chromatin.

What is a dihybrid cross?

A cross that examines the inheritance of two different traits.

What is an SNP (Single Nucleotide Polymorphism)?

A single base pair variation in the DNA sequence among individuals.

What is meiotic recombination?

The exchange of genetic material between homologous chromosomes during meiosis.

What is a gene drive?

A genetic engineering technology that promotes the inheritance of a particular gene to increase its prevalence in a population.

What is a phenotype ratio?

The ratio of different phenotypes produced in offspring from a genetic cross.

What is a DNA profile?

A unique representation of an individual's DNA characteristics used for identification.

What is genetic linkage?

The tendency of genes located close together on a chromosome to be inherited together.

What is a causative gene?

A gene that has been demonstrated to cause a particular disorder or phenotype.

What are telomeres?

Repeated DNA sequences at the ends of chromosomes that protect them from deterioration.

What is a polyploid organism?

An organism that has more than two complete sets of chromosomes.

What is the definition of dosage compensation?

A mechanism to equalize the expression of genes between individuals with differing gene doses.

What is the role of the centromere?

The region of a chromosome where the two sister chromatids are joined together.