Mendelian Genetics 10

What is the Principal of Segregation in inheritance?

Each parent contributes one of two possible alleles for a trait to their child, which are separated during meiosis.

What does the Law of Independent Assortment state?

The inheritance of one trait does not affect the inheritance of another trait, allowing traits to be inherited separately and randomly assorted during meiosis.

Where are chromosomes found and what is their role?

Chromosomes are found within the nucleus of cells and carry genetic information in the form of DNA and proteins, ensuring accurate DNA copying during cell division.

What is heredity?

The passing of chromosomes from parent to offspring.

What are unit characters in genetics?

Unit characters are individual traits or characteristics that can be passed from parents to offspring.

What are discrete traits?

Discrete traits have distinct options rather than a smooth range of possibilities, such as red or white, but not light red.

What are genes?

Genes are inherited factors that determine characteristics.

What is the haploid number of chromosomes?

The haploid number (1n) is the number of chromosomes in a cell that has one set of chromosomes, which is 23 in humans.

What is the diploid number of chromosomes?

The diploid number (2n) is the total number of chromosomes in a cell that has two complete sets, which is 46 in humans.

What is a zygote in the context of development?

A zygote is the first stage of a new organism's life, formed when a sperm cell combines with an egg cell.

What does homozygote mean?

A homozygote is a true-breeding individual with both alleles of a gene the same, producing only one type of gamete.

What is a heterozygote?

A heterozygote is an individual with two different alleles of a gene, producing two types of gametes.

What is true breeding?

True breeding helps understand how alleles are inherited and expressed, often demonstrated by crossing two homozygous plants.

What is sickle cell anemia?

Sickle cell anemia develops when a person inherits two mutated copies of a gene for hemoglobin, causing red blood cells to form a sickle shape.

What is the P generation in genetics?

The P generation refers to the initial cross or the parent generation.

What is the F1 generation?

The F1 generation is the offspring of the P generation (parents).

What is the F2 generation?

The F2 generation is the offspring of the F1 generation.

What is a monohybrid?

A monohybrid is an F1 heterozygote produced from a cross that involves a single character.

What is a monohybrid cross?

A monohybrid cross is a cross between two individuals that are each heterozygous for the same pair of alleles.

What is probability in genetics?

Probability is the mathematical chance of an outcome occurring, such as the random fertilization of an egg by a sperm. Either 1 or 0

What is the product rule in probability?

The product rule states to multiply the probabilities of independent events occurring together.
Ex. rolling a 4 AND a 4 again.  ⅙ x ⅙ = 1/36 

What is the sum rule in probability?

The sum rule states to add the probabilities of either instance occurring

Ex. rolling a 4 OR a 3. ⅙ + ⅙ = 2/6

What are digenic traits?

Digenic traits involve more than one gene, where two different genes contribute to a single trait or characteristic in an organism.

What is a phenotype?

Phenotype refers to the observable characteristics or traits of an organism, including physical appearance, behavior, and biochemical properties.

What does genotype mean?

Genotype refers to the genetic constitution of an organism in terms of genes and alleles.

What is a dominant allele?

A dominant allele is phenotypically expressed, masking the effect of a recessive allele.

What is a recessive allele?

A recessive allele is one that is masked by a dominant allele and is not phenotypically expressed.

What is incomplete dominance?

Incomplete dominance occurs when the traits of two parents blend together in their offspring, such as a red and white flower producing a pink one.

What is codominance?

Codominance is when both alleles are fully expressed in the phenotype, resulting in both traits appearing together without blending, such as a brown dog with white spots.

What are multiple alleles?

Multiple alleles exist when a single gene has more than two different versions.

What is epistasis?

Epistasis occurs when one gene can hide or change the effect of another gene, inhibiting the expression at a different locus.

What is polygenic inheritance?

Polygenic inheritance refers to traits that are influenced by multiple genes, such as skin color and human height, often producing a bell-shaped curve.

What is pleiotropy?

Pleiotropy is when a single gene's expression impacts multiple physiological processes or systems, often influenced by the environment.

What is an intermediate phenotype?

An intermediate phenotype is a trait that appears as a blend of two different traits, such as wavy hair resulting from curly and straight hair.

What are quantitative traits?

Quantitative traits are characteristics influenced by multiple genes, showing a range of variations and measurable characteristics.

What is a testcross?

A testcross is a cross between an individual with a dominant phenotype and a homozygous recessive individual, used to determine if the dominant trait individual is heterozygous or homozygous.

How can a geneticist determine if an individual with a dominant trait is heterozygous or homozygous using a testcross?

If half of the offspring have the dominant trait and half have the recessive trait, the tested individual is a heterozygote; if all offspring express the dominant trait, the tested individual is homozygous.

What is a dihybrid?

A dihybrid is an F1 individual that is heterozygous for two characters and produced from a cross involving two genes.

What is a dihybrid cross?

A dihybrid cross is a cross between two individuals that are each heterozygous for pairs of alleles of two genes.

What does the 9:3:3:1 ratio represent in genetics?

The 9:3:3:1 ratio represents the expected phenotypic ratio in a dihybrid cross, where 9 individuals show both dominant traits, 3 show one dominant and one recessive trait, and 1 shows both recessive traits.

What are reciprocal crosses?

Reciprocal crosses are used to determine if inheritance is influenced by sex chromosomes by switching the roles of males and females in the crosses.

What is independent assortment?

Independent assortment refers to the principle that traits of different characters are distributed to offspring independently and are not inherited together.

What is a locus?

A locus is the specific location of a gene on a chromosome.

What is linkage in genetics?

Linkage refers to the tendency of alleles that are close together on chromosomes to be inherited together; they are less likely to be separated during crossing over.

Who is Walter Sutton and what is his contribution to genetics?

Walter Sutton proposed the chromosome theory of inheritance, stating that genes and their alleles are carried on chromosomes.

What do squares and circles represent in pedigrees?

In pedigrees, squares represent males and circles represent females.

How do recessive and dominant traits appear in pedigrees?

Recessive traits typically skip generations while dominant traits generally do not skip generations.

What is an example of a trait affected by multiple alleles, dominance, and codominance?

Blood type is an example of a trait influenced by multiple alleles, dominance, and codominance.

Which chromosome carries the genes for eye color?

The genes for eye color are carried on the X chromosome.

What is the charge of DNA and its movement in an electric field?

DNA is negatively charged and will move toward the positive side in an electric field because like charges repel each other.

What is the genotype of females in terms of sex chromosomes?

Females inherit two X chromosomes, one from each parent, giving them the genotype XX.

What is the genotype of males in terms of sex chromosomes?

Males inherit an X chromosome from their mother and a Y chromosome from their father, giving them the genotype XY.

How do sex chromosomes influence somatic traits?

Sex chromosomes carry genes for somatic traits, affecting abilities like color vision and setting up distinct patterns of inheritance related to these abilities.

Is there a predisposition to certain blood types based on sex?

There has been no indication that one sex is more prone to inherit a particular blood type over the other.