Genetic Variation Sources and Effects in Biology: Population and Individual Perspectives

What is the primary source of completely new alleles?

Mutation, defined as a permanent, random change in the DNA base sequence.

What distinguishes somatic mutations from gametic mutations?

Somatic mutations occur in body cells and are not inherited, while gametic mutations occur in sex cells and can be inherited.

How does sexual reproduction contribute to genetic variation?

It creates unique gametes through meiosis, involving independent assortment and crossing over, leading to new combinations of alleles during fertilization.

What factors can affect allele frequencies in a population?

Small population size (genetic drift/bottlenecks), differing survival rates, migration (gene flow), and non-random mating.

What is the phenotypic impact of genetic variation?

It connects genetic changes (genotype/allele) to observable physical traits (phenotype), affecting how an organism functions or interacts with its environment.

How can genetic variation influence survival and adaptability?

Variations can be beneficial or harmful, helping populations survive environmental changes by ensuring certain individuals are better suited to survive and reproduce.

What is gene tracking?

A method to identify the presence or absence of specific genes, DNA sequences, or genetic markers in individuals or populations.

What is a common purpose of gene tracking in conservation management?

To find unrelated individuals to breed, reducing inbreeding depression and increasing genetic diversity in endangered species.

How does gene tracking assist in health and disease management?

It helps identify carriers of mutant alleles or track inherited disease risk, such as susceptibility to conditions like HIV.

What is the purpose of establishing lineage through gene tracking?

To determine parentage or familial relationships within a population or pedigree.

What is the definition of genetic variation?

The range or differences in alleles and traits among individuals of the same species.

Define allele.

An alternative form of the same gene, caused by a different base sequence.

What is the difference between genotype and phenotype?

Genotype is the specific allele combination an organism carries, while phenotype is the observable physical expression of that genotype.

What is a dominant allele?

An allele that is always expressed in the phenotype if present, represented by an upper-case letter.

What is a recessive allele?

An allele that is expressed in the phenotype only when two copies are present (homozygous), represented by a lower-case letter.

What does it mean to be homozygous?

Having two identical alleles for a particular trait.

What does it mean to be heterozygous?

Having two different alleles for a particular trait.

What is a gamete?

A sex cell (sperm or egg) containing half the normal number of chromosomes.

What is a zygote?

A fertilized egg formed by the fusion of male and female gametes.

What is a pedigree chart?

A diagram showing the phenotypes and family relationships of related individuals across generations.

What is the nature of genetic variation?

The biological or physical impact caused by changes in genetic variation over time within an individual or population.

How can genetic variation lead to beneficial outcomes?

It can increase resistance to specific diseases or lead to advantageous phenotypic traits in changing environments.

What is the significance of gene flow in populations?

Gene flow introduces new alleles into a population, affecting genetic diversity and allele frequencies.

What is the role of non-random mating in genetic variation?

It can alter allele frequencies by favoring certain traits over others, impacting the genetic structure of a population.

What is the impact of small population size on genetic variation?

It can lead to genetic drift and bottlenecks, reducing genetic diversity and increasing the risk of inbreeding.

What is the role of mutation in evolution?

Mutations are the primary source of new alleles, providing the raw material for natural selection to act upon.

How does meiosis contribute to genetic diversity?

Meiosis creates gametes with unique combinations of alleles through processes like independent assortment and crossing over.