Chapter 9: Genetics, Patterns of Inheritance Flashcards
Genetics
Scientific study of heredity.
Heredity
Transmission of traits from one generation to the next.
Hybrids
Offspring of two true-breeding varieties.
Offspring resulting from combining the qualities of two organisms of two different varieites or species.
Character
Heritable features that vary among individuals.
Trait
Variant of character
Specific characteristic of an individual
Homozygous Trait
the same trait from both parents
For example: AA or aa
Heterozygous
Different traits from each parent
For example: Aa
Alleles
Two different versions of genes for each trait.
Homozygous Alleles
Alleles are identical
Heterozygous Alleles
Alleles are different
Dominant Allele.
The allele that determines the appearance of the organism.
Recessive Allele
The other allele, which has no noticeable effect on the appearance.
How many alleles does a gamete carry?
One allele from each inherited character.
Punnett Square
Highlights the four possible combinations of gametes and offspring that result from each cross.
Phenotype
An organism’s physical trait (what you can see)
Genotype
An organism’s genetic makeup (what you cannot see)
Monohybrid Crosses
A cross between two individuals that differ in only one character.
Examples: flowers 3 are purple and one is white.
Dihybrid Cross
The crossing of parental varieties differs in TWO characters
Example: the peas, color and round/wrinkled
Testcross
An individual of the dominant phenotype (but with an unknown genotype)
What is the Law of Independent Assortment ?
The inheritance of one character does not affect the inheritance of another.
What is the Law of Segregation
The two alleles for characteristics segregate (separate) from each other during the production of gametes retaining their individuality.
What is the Law of Dominance?
Alleles will act in a way that dominant alleles will mask recessive alleles.
Incomplete Dominance
F1 hybrids have an appearance in between the phenotypes of the two parents.
Codominance
When the effect of the two alleles is equally visible in the phenotype of the heterozygote.
They are being equally expressed.
Pleiotropy
One mutant gene affects several different characteristics.
Polygenic Inheritance
Additive effects of two or more genes on a single phenotype.
These traits are controlled by multiple genes and/or influenced by the environment.
suchas height or skin pigmentation
Epistasis
One gene alters the expression of another gene
Linked Genes
Are located closed together on a chromosomes
they may be inherited together
Epigenetic Inheritance
The transmission of traits by mechanisms not directly involving DNA sequence.
DNA and protein components of chromosomes can be chemically modified.
What are some environmental factors that play a role in epigenetic inheritance?
Temperature
Solar Light
Drugs and chemicals
diet
oxygen levels.
Family pedigree
Shows the HISTORY of a trait in a family.
Wild-Type Traits
Those seen most often in nature
Carriers of Disorders
Individuals who have the recessive allele but appear normal.
Who determines the sex of the offspring?
Males with the XY chromosome
Sex Linked Genes
Only genes that are located on a set of chromosomes. Specifically chromosome #23
