Genetic Variation Flashcards

1
Q

What is an allele?

A

A variant form of a gene. Alleles can be dominant or recessive and are responsible for genetic variation.

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2
Q

What is a gene?

A

A segment of DNA that codes for a specific protein or function, determining individual traits.

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3
Q

What is a chromosome?

A

A structure made of DNA and protein that contains genes. Humans have 46 chromosomes in each somatic cell.

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4
Q

What is a genotype?

A

The genetic makeup of an organism, consisting of alleles inherited from both parents (e.g., Aa, BB).

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5
Q

What is a phenotype?

A

The physical expression of an organism’s genotype, including observable traits.

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6
Q

What does homozygous mean?

A

Having two identical alleles for a particular gene (e.g., AA or aa).

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7
Q

What does heterozygous mean?

A

Having two different alleles for a particular gene (e.g., Aa).

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8
Q

What is a dominant allele?

A

An allele that expresses its trait in the phenotype even when only one copy is present (e.g., A in Aa).

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9
Q

What is a recessive allele?

A

An allele that is masked by a dominant allele and only expressed in the phenotype when two copies are present (e.g., aa).

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10
Q

What is codominance?

A

A form of inheritance where both alleles are fully expressed in the phenotype of a heterozygote (e.g., AB blood type).

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11
Q

What is incomplete dominance?

A

A genetic situation where neither allele is dominant, resulting in a blending of traits in the heterozygote (e.g., red and white flowers produce pink).

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12
Q

What is a mutation?

A

A change in the DNA sequence, which can introduce new genetic variations.

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13
Q

What is genetic drift?

A

Random changes in allele frequencies in a population, often having a more significant effect in small populations.

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14
Q

What is gene flow?

A

The transfer of genetic material between different populations, increasing genetic variation within the population.

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15
Q

What is natural selection?

A

A process where organisms with favorable traits are more likely to survive and reproduce, leading to changes in allele frequencies over time.

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16
Q

What is sexual reproduction?

A

The process of creating offspring through the combination of male and female gametes, resulting in genetic variation.

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17
Q

What is crossing over?

A

The exchange of genetic material between homologous chromosomes during meiosis, creating new allele combinations.

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18
Q

What is independent assortment?

A

The random distribution of homologous chromosomes during meiosis, resulting in genetic variation.

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19
Q

What is fertilization?

A

The fusion of male and female gametes to form a zygote, combining alleles from both parents.

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20
Q

What are polygenic traits?

A

Traits controlled by two or more genes, often resulting in a continuous range of phenotypes (e.g., skin color, height).

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21
Q

What is genetic variation?

A

The diversity in gene frequencies within a population, essential for evolution and adaptation.

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22
Q

What is the bottleneck effect?

A

A sharp reduction in population size due to environmental events, reducing genetic variation.

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23
Q

What is the founder effect?

A

Reduced genetic variation that occurs when a small group of individuals establishes a new population.

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24
Q

What is meiosis?

A

A type of cell division that reduces the chromosome number by half, creating four genetically unique gametes.

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25
Q

What does diploid mean?

A

A cell or organism with two sets of chromosomes (one from each parent), typical of somatic cells.

26
Q

What does haploid mean?

A

A cell or organism with one set of chromosomes, typical of gametes (sperm and egg cells).

27
Q

What is a zygote?

A

The cell formed by the fusion of two gametes during fertilization, containing a full set of chromosomes.

28
Q

What is a gene pool?

A

The complete set of genetic information within all individuals in a population.

29
Q

What is selection pressure?

A

External factors that affect an organism’s survival, influencing natural selection (e.g., predators, climate).

30
Q

What is speciation?

A

The process through which new species arise due to genetic isolation and evolutionary processes.

31
Q

What is genetic recombination?

A

The process of forming new combinations of alleles during meiosis, including crossing over and independent assortment.

32
Q

What is phenotypic variation?

A

Differences in physical appearance or function among individuals in a population, often due to genetic and environmental factors.

33
Q

What is somatic mutation?

A

A mutation occurring in a somatic (non-reproductive) cell that affects only the individual and is not passed to offspring.

34
Q

What is germline mutation?

A

A mutation in a reproductive cell that can be inherited by offspring, potentially affecting future generations.

35
Q

What is a point mutation?

A

A mutation affecting a single nucleotide in the DNA sequence, which may be silent, missense, or nonsense.

36
Q

What is a silent mutation?

A

A point mutation that does not change the amino acid sequence of a protein and therefore has no effect on its function.

37
Q

What is a missense mutation?

A

A mutation that changes one amino acid in a protein sequence, potentially altering the protein’s function.

38
Q

What is a nonsense mutation?

A

A mutation that converts a codon for an amino acid into a stop codon, resulting in a shortened, often nonfunctional protein.

39
Q

What is a frameshift mutation?

A

A mutation caused by insertions or deletions of nucleotides that alter the reading frame, leading to a completely different amino acid sequence.

40
Q

What is genetic linkage?

A

The tendency for genes located close to each other on the same chromosome to be inherited together.

41
Q

What is pleiotropy?

A

A genetic scenario where one gene influences multiple, seemingly unrelated phenotypic traits.

42
Q

What is epistasis?

A

An interaction between genes where the effect of one gene is modified or masked by another gene.

43
Q

What is a sex-linked trait?

A

A trait associated with a gene that is located on a sex chromosome, often leading to different expression in males and females.

44
Q

What is an autosomal trait?

A

A trait associated with a gene located on an autosome (non-sex chromosome), typically affecting males and females equally.

45
Q

What is genetic equilibrium?

A

A state where allele frequencies in a population remain constant over generations in the absence of evolutionary forces.

46
Q

What is the Hardy-Weinberg principle?

A

A principle stating that allele and genotype frequencies in a population remain constant if no evolutionary influences are acting.

47
Q

What is adaptation?

A

A heritable trait that enhances an organism’s ability to survive and reproduce in its environment.

48
Q

What is fitness?

A

The reproductive success of an organism in passing its genes to the next generation, relative to others in the population.

49
Q

What are homologous chromosomes?

A

A pair of chromosomes, one from each parent, that contain the same genes but may have different alleles.

50
Q

What are recombinant chromosomes?

A

Chromosomes that have undergone crossing over, resulting in a mix of alleles from both parental chromosomes.

51
Q

What is evolution?

A

The change in allele frequencies in a population over time, often leading to adaptation and speciation.

52
Q

What is artificial selection?

A

The intentional breeding of organisms to enhance or suppress specific traits.

53
Q

What is genetic isolation?

A

A state where two populations cannot interbreed, often leading to speciation due to a lack of gene flow.

54
Q

What is a monohybrid cross?

A

A genetic cross focusing on the inheritance of a single trait controlled by two alleles.

55
Q

What is a dihybrid cross?

A

A genetic cross involving two traits, where each trait is controlled by two alleles, following Mendel’s law of independent assortment.

56
Q

What is a locus?

A

The specific physical location of a gene or allele on a chromosome.

57
Q

What is a carrier?

A

An individual who has one copy of a recessive allele that can be passed to offspring but does not express the trait.

58
Q

What is genetic engineering?

A

The manipulation of an organism’s genome using biotechnology, often to add or modify traits.

59
Q

What is biotechnology?

A

The use of living organisms or their components to develop products, often used in genetics for research and applications.

60
Q

allele frequency

A

the proportion of a specific allele amoung all allele copies in an population. Changes in the allele frequency over time can indicate evolutionary changes within the population