Flashcards
Genetic Variation Flashcards
Cards in this deck (42)
- 1AlleleAlternate forms of a gene
- 2Homologous ChromosomesA pair of chromosomes, one from the mother and the other from the father. The maternal and paternal chromosomes in a homologous pair have the same genes at the same loci, but possibly different alleles.
- 3LocusThe position along the chromosome that a gene is located.
- 4HeterozygousIndividuals who are heterozygous for a certain gene carry two different alleles.
- 5HomozygousIndividuals who are homozygous for a certain gene carry two copies of the same allele.
- 6MaternalChromosomes originating from an individuals mother's egg.
- 7PaternalChromosomes originating from an individuals father's sperm.
- 8MutationA gene mutation is a permanent alteration in the DNA base sequence that makes up a gene, can create new alleles, new genotypes and may create new phenotypes. Mutation is the source of all new alleles.
- 9PhenotypeThe physical expression of individuals genotypes.
- 10GenotypeThe genetic makeup of the individual, it determines the potential of the individual.
- 11Environmental factorsEnvironmental factors influence the expression of the genotype in the phenotype. Can be external (Temperature, biotic factors) or internal (hormones).
- 12MeiosisCell division the produces sex cells (gametes).
- 13Mendel's Law of Particulate inheritanceCharacteristics of both parents are passed on to subsequent generations as discrete entities(genes).
- 14Mendel's Law of SegregationDuring metaphase 2 in meiosis, the two members of any homologous chromosome pair segregate unchanged and are passed into different gametes/random segregation of chromotids.
- 15Mendel's Law of independent assortmentEach Homologous pair of chromosomes is sorted independently of the other pairs into intermediary cells which greatly increases variation/random segregation of chromosomes.
- 16Basic Punnet square4 possible Genotypes, phenotypic ratios differ depending on the genotype of the parents
- 17Dihybrid Cross
- 18Test CrossMating of an unknown genotype with a homozygous recessive to determine the unkown genotype through the phenotypic ratios of the offspring.
- 19Monohybrid crossStudies the inheritance pattern of one gene, offspring occur in predictable ratios.
- 20CodominanceA genetic scenario where neither allele is dominant or recessive and both get expressed is known as codominance.
- 21Crossing OverCrossing over is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes during meiosis.
- 22Linked GenesWhen two genes are close together on the same chromosome, they do not assort independently and are said to be linked.
- 23TripletGroup of three nucleic bases
- 24Deletion MutationDeletions are mutations in which a section of DNA is lost, or deleted.
- 25Insertion MutationInsertions are mutations in which extra base pairs are inserted into a new place in the DNA.
- 26Substitution MutationA substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G).
- 27FrameshiftSince protein-coding DNA is divided into codons three bases long, insertions and deletions can alter a gene so that its message is no longer correctly parsed. These changes are called frameshifts.
- 28Causes of MutationLight, Radiation, Chemicals or DNA replication errors.
- 29Somatic Cell MutationsAre not inheritable
Occurs in only the one individual
Not added to gene pool - 30Gametic Cell MutationsInheritable
Not Limited to one individual
Is added to gene pool - 31Gene PoolThe stock of different genes (therefore alleles) in an interbreeding population.
- 32Genetic VariationCreates differences in individuals that could be advantageous for survival.
- 33MigrationThe movement of genes (therefore alleles) from one population into another.
- 34EmigrationLeaving a population
- 35ImmigrationJoining a population
- 36Factors Influencing MigrationBarriers(usually physical), Mobility, Choice(usually by females)
- 37Genetic DriftVariation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce. Effects are greater in smaller populations.
- 38Natural SelectionThe process where organisms that are better suited to an environment generally survive and produce offspring.
- 39Chatham Island Black RobinsOriginated from a single female bird named Blue
No inbreeding effects may be due to blues recessive alleles being beneficial or silent as well. - 40Incomplete DominanceIncomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.
- 41Lethal AllelesLethal Alleles are alleles that cause death when expressed in homozygous conditions
- 42Pure Breeding Dihybrid InhereitanceDominant: Only tell by cross breeding with a homozygous recessive (test cross)
Recessive: Shows all phenotypes
If Genes are linked it is very difficult to breed as they will be inherited together.
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- NCEA Level 2 Physics Flashcards on Genetic Variation Flashcards, created by Adam Donaldson on 19/10/2016.
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