Genetic Variation and Change Flashcards
Heredity
The biological process whereby genetic factors are transmitted from one generation to the next
Allele
An alternative form of a gene
Gene
A segment of DNA on a chromosome that codes for a protein
Genotype
Genetic makeup of an organism; an organisms combination of alleles
Phenotype
An organisms appearance or other detectable characteristics that results from the organisms genotype and the environment
Gene Pool
All of the alleles in all the individuals that make up a population
Allele Frequency
The number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the same gene
Genetic Biodiversity
The range of all the alleles present in the gene pool
Natural Selection
Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest
Mutation
A sudden and permanent change to the base sequence of DNA
Gene Mutation
A change in the sequence of the bases in a gene, which changes the structure of the polypeptide that gene codes for
Triplet
The three nucleotides of DNA which code for one amino acid
Meiosis
Reduction cell division that produces haploid cells for the purposes of sexual reproduction
Somatic Cell
Any of the cells of a plant or animal except the reproductive cells
Gametic Cell
A sex cell
Diploid
An organism or cell having two sets of chromosomes or twice the haploid number
Homologous Chromosomes
Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organisms father, the other from the mother
Chromatid
One of two identical strands into which a chromosome splits during mitosis
Centromere
The region of the chromosome that holds the two sister chromatids together during mitosis
Tetrad
The four chromatids in a pair of homologous chromosomes that come together as a result of synapsis during meiosis
Crossing Over
The exchange of genetic material between homologous chromosomes during meiosis; can result in genetic recombination
Segregation
The separation of paired alleles during meiosis so that members of each pair of alleles appear in different gametes
Independent Assortment
The random way in which chromosome line up and are split into the gametes. It results in genetic variation
Autosome
A chromosome that is not a sex chromosome
Monohybrid
Genetic crosses that involve one trait
Complete Dominance
A relationship in which one allele is completely dominant over another
Pure Breeder
An individual is homozygous for a trait and can only pass one type of allele to its offspring
Incomplete Dominance
A condition in which a trait in an individual is intermediate between the phenotype of the individual’s two parents because the dominant allele is unable to express itself fully
Co-dominance
A pattern of inheritance when the two alleles of a gene are neither dominant or recessive, the two alleles are both expressed. (For example, B=black features, W=white feathers, BW=black and white features)
Multiple Alleles
A gene with three or more alleles
Lethal Alleles
Mutated genes that are capable of causing death
Dihybrid Inheritance
A genetic cross involving genes at two different loci. The inheritance of one pair of alleles does not affect the inheritance of the other pair because chromosomes act independently of one another during gamete formation.
Linked Genes
Genes located on the same chromosome that tend to be inherited together in genetic crosses
Gamete
An egg or sperm sex cell that contains a single set of chromosomes, one from each homologous pair
Genetic Change
Changes to allele frequencies and or the gene pool
Gene Pool
Combined genetic information of all the members of a particular population
Allele Frequency
The number of times an allele occurs in a gene pool, compared to the total number of alleles in that pool for the same gene
Sexual Selection
A form of natural selection which individuals with certain inherited characteristics are more likely than other individuals to obtain mates
Adaptation
inherited characteristic that improves an organisms ability to survive and reproduce in a particular environment
