Genetics Quiz Flashcards
sequence of DNA that codes for a protein and thus determines a trait
gene
one of a number of different forms of a gene
alleles
offspring of crosses between parents with different traits
hybrid
a trait that will appear in the offspring if one of the parents contributes it
dominant
a trait that will not be shown in the offspring if one of the parents contributes a dominant trait in each genotype.
recessive
term used to refer to an organism that has the same two alleles for a particular trait
homozygous
term used to refer to an organism that has two different alleles for the same trait
heterozygous
specialized cell involved in sexual reproduction
gamete
a fertilized egg
zygote
the union of male and female gametic nuclei
fertilization
when individuals with contrasting traits are crossed, the offspring will express only the dominant trait
Principle of Dominance
The two members of a gene pair separate from each other in the formation of gametes. Half the gametes carry one allele, and the other half carry the other allele.
Principle of Segregation
Principle originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.
Principle of Independent Assortment
situation in which one allele isn’t completely dominant over another.
Incomplete dominance
situation in which both alleles of a gene contribute to the phenotype of the organism
codominance
gene located on the X or Y chromosome
X-linked trait
chart that shows the relationships within a family
pedigree
Any chromosome except for the sex chromosomes. Humans have 44 autosomal chromosomes
autosomal chromosomes
A trait that is controlled by a group of nonallelic genes.
polygenic traits
three or more alleles of the same gene
multiple alleles
one of two chromosomes that determine an individual’s sex, females have two X chromosomes, male have one X and one Y chromosome.
sex chromosomes
a set of photographs of chromosomes grouped in order of pairs
karyotype
error in meiosis in which homologous chromosomes fail to separate
nondisjunction
a chromosomal rearrangement in which a segment of genetic material from one chromosome becomes heritably linked to another chromosome
translocation
a type of chromosomal aberration in which the position of a segment of the chromosome is changed in such a way that the linear order of the genes is reversed.
inversion
term used to refer to a cell that contains both sets of homologous chromosomes.
diploid
term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes
haploid
analysis of sections of DNA that have little or no known function, but vary widely from one individual to another, in order to identify individuals.
DNA fingerprinting
member of a population of genetically identical organisms produced from a single cell.
cloning
combined genetic information of all the members of a particular population.
gene pool
number of times an allele occurs in a gene pool compared with the number of times other alleles occur.
relative frequency
process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest.
natural selection
the application of genetic engineering to the transplantation of genes into human cells in order to cure a disease caused by a genetic defect, as a missing enzyme.
gene therapy
method of improving a species by allowing only those individual organisms with desired characteristics to produce the next generation.
selective breeding
