Inheritance Flashcards
What is a gene?
A gene is a sequence of DNA that codes for a specific protein or functional RNA.
What is an allele?
An allele is a variant form of a gene that can produce different characteristics in an organism.
What is the difference between dominant and recessive alleles?
Dominant alleles are expressed in the phenotype even when only one copy is present (heterozygous), while recessive alleles are only expressed when two copies are present (homozygous).
What is a homozygous genotype?
A homozygous genotype has two identical alleles for a particular gene, either both dominant or both recessive (e.g., AA or aa).
What is a heterozygous genotype?
A heterozygous genotype has two different alleles for a particular gene, one dominant and one recessive (e.g., Aa).
What is co-dominance?
Co-dominance occurs when both alleles contribute equally and visibly to the phenotype in a heterozygote (e.g., AB blood type).
What is incomplete dominance?
Incomplete dominance is when the phenotype of the heterozygote is intermediate between the two homozygotes (e.g., red and white flowers producing pink flowers).
What is a Punnett square used for?
A Punnett square is a diagram used to predict the genetic outcomes of a cross between two individuals, showing the possible genotypes of offspring.
What is the phenotypic ratio in a monohybrid cross for two heterozygous parents?
The phenotypic ratio in a monohybrid cross between two heterozygous parents is 3:1, with three individuals showing the dominant phenotype and one showing the recessive phenotype.
What is a dihybrid cross?
A dihybrid cross is the genetic cross between two organisms that examines the inheritance of two traits simultaneously.
What is the phenotypic ratio in a dihybrid cross for two heterozygous parents?
The phenotypic ratio in a dihybrid cross for two heterozygous parents is 9:3:3:1, with four possible phenotypes in the offspring.
What is the law of segregation?
The law of segregation states that during gamete formation, the two alleles for each gene separate, so that each gamete only carries one allele for each gene.
What is the law of independent assortment?
The law of independent assortment states that genes for different traits segregate independently of each other during gamete formation.
What is genetic linkage?
Genetic linkage occurs when two or more genes are located close to each other on the same chromosome and are inherited together more often than expected by chance.
What is a test cross?
A test cross is a genetic cross used to determine the genotype of an individual showing the dominant phenotype by crossing it with a homozygous recessive individual.
What is a carrier in terms of genetic inheritance?
A carrier is an individual who has one copy of a recessive allele for a genetic disorder but does not show the disorder because the other allele is dominant.
What is the difference between autosomal and sex-linked inheritance?
Autosomal inheritance involves genes located on non-sex chromosomes, while sex-linked inheritance involves genes located on sex chromosomes (X or Y).
What is the significance of X-linked inheritance?
X-linked inheritance refers to the inheritance of genes located on the X chromosome. Males are more likely to express X-linked recessive traits because they have only one X chromosome.
What is an example of an X-linked genetic disorder?
An example of an X-linked genetic disorder is hemophilia, which affects blood clotting and is more common in males due to the single X chromosome.
What is polygenic inheritance?
Polygenic inheritance involves the control of a characteristic by multiple genes, often resulting in continuous variation (e.g., height, skin color).
What is epistasis?
Epistasis is when one gene affects the expression of another gene, typically through the interaction between different alleles or genes.
What is a mutation?
A mutation is a change in the DNA sequence that can result in a new allele. Mutations can be beneficial, neutral, or harmful to an organism.
