Post-test 1 (Mendelian genetics)

Phenotype

Physical appearance of an organism

First filial generation (F1)

The first generation of offspring produced from a cross between two parental organisms. One phenotype (dominant) was present 100% of the time.

F2

Phenotype reappeared and disappeared (recessive). The second generation of offspring resulting from a cross between the F1 generation. This generation exhibits a mixture of dominant and recessive phenotypes.

Allele

Different forms of a gene that determine specific traits in an organism, where each individual carries two alleles for each gene, one inherited from each parent.

Homozygous

Having two identical alleles for a specific gene. AA or aa

Heterozygous

Having two different alleles for a specific gene, such as Aa.

Punnett Square

A diagram used to predict the genotypic and phenotypic ratios of offspring from a cross between two individuals. It visually represents all possible combinations of alleles from the parents.

Diploid

Having two complete sets of chromosomes, one from each parent, in a cell. 2n where n represents one set of chromosomes

Zygote

The initial cell formed when a sperm cell fertilizes an egg cell, containing genetic material from both parents.

Haploid

Having a single set of chromosomes, represented by n, typical of gametes in sexual reproduction.

Monohybrid cross

A genetic cross between two individuals that examines the inheritance of a single trait, typically involving one homozygous dominant and one homozygous recessive parent.

Dihybrid cross

A genetic cross between two individuals that examines the inheritance of two different traits, typically involving parents that are both heterozygous for both traits.

Genotype

The genetic makeup of an individual, consisting of the specific alleles for a given trait, which can be homozygous or heterozygous.

Law of independent inheritance

The principle stating that the alleles for different traits segregate independently of one another during gamete formation, leading to genetic variation in offspring.

ABO blood groups

A system for classifying human blood based on the presence or absence of antigens, which are determined by specific alleles. The main blood types are A, B, AB, and O, with implications for blood transfusions and compatibility.

Type B

blood type in the ABO system, characterized by the presence of B antigens on the surface of red blood cells.

Type A

blood type in the ABO system, characterized by the presence of A antigens on the surface of red blood cells.

Type AB

blood type in the ABO system, characterized by the presence of both A and B antigens on the surface of red blood cells.

Type O

blood type in the ABO system, characterized by the absence of A and B antigens on the surface of red blood cells.

I^A

dominant allele for type A blood in the ABO blood group system.

I^AI^B

genotype that produces type AB blood, possessing both A and B alleles.

i/i

genotype that produces type O blood, characterized by the absence of A and B alleles.

I^AI^A

homozygous genotype for type A blood, expressing the dominant A allele.

Epistasis

a genetic interaction where one gene's expression is affected by another gene. It can mask or modify the phenotypic expression of traits.