Mendelian Genetics Flashcards
What is meiosis and its role in the life cycle?
Meiosis creates genetic diversity through the role of homologous chromosomes and alleles in inheritance
Meiosis is essential for sexual reproduction and leads to the formation of gametes.
Define alleles.
Different versions of a gene, inherited from each parent, which can lead to varied protein functions
Alleles are crucial for genetic variation within a population.
What are dominant and recessive alleles?
Dominant alleles result in functional enzymes (e.g., yellow seeds), while recessive alleles lead to non-functional enzymes (e.g., green seeds)
The example of pea seed coloration illustrates this concept.
What is the Law of Dominance?
One allele can mask the expression of another
This law explains how certain traits can dominate over others in phenotype.
What does the Law of Segregation state?
Alleles separate during gamete formation, ensuring offspring receive one allele from each parent
This principle is fundamental to understanding inheritance patterns.
Explain the Law of Independent Assortment.
Genes for different traits are inherited independently if located on separate chromosomes
This law allows for the combination of traits in various ways.
What is a monohybrid cross?
A genetic cross that illustrates a 3:1 phenotypic and 1:2:1 genotypic ratio in F2 generations
Monohybrid crosses focus on one trait at a time.
What is a dihybrid cross?
A genetic cross that demonstrates a 9:3:3:1 phenotypic ratio when analyzing two traits (e.g., seed color and texture)
Dihybrid crosses involve two traits and showcase the Law of Independent Assortment.
What is the purpose of Punnett squares?
To predict offspring ratios
Punnett squares visually represent the genetic combinations from a cross.
What is a test cross?
A cross between an individual with the dominant phenotype and a homozygous recessive individual to determine genotype
Test crosses help identify whether an individual with a dominant trait is a heterozygote or homozygote.
What is incomplete dominance?
Results in an intermediate phenotype (e.g., pink flowers from red and white parents)
Incomplete dominance occurs when the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.
What is codominance?
Both alleles are expressed equally (e.g., spotted patterns in animals, ABO blood groups)
In codominance, both alleles in a heterozygote contribute to the phenotype, resulting in traits that are neither dominant nor recessive.
What are polygenic traits?
Traits influenced by multiple genes, leading to a continuous range of phenotypes (e.g., human height)
Polygenic inheritance results in a bell-shaped curve of phenotypes in a population.
What is epistasis?
Interaction between genes where one gene’s activity depends on another’s (e.g., coat color in dogs)
Epistasis can mask the effects of other genes, influencing the phenotype in complex ways.
What is pleiotropy?
A single gene influencing multiple traits (e.g., clasp-1 mutants in plants causing varied developmental issues)
Pleiotropic effects can complicate the understanding of genetic inheritance and trait expression.
