Mendelian Inheritance Flashcards

Flashcards covering vocabulary terms related to Mendelian Inheritance.

Remove anthers

The process of removing the anthers from a flower in order to control pollination.

Transfer pollen

The transfer of pollen from the anthers of one flower to the stigma of another flower.

First-generation offspring

The offspring of the parental generation (P generation).

Traits

The different forms of a characteristic or feature.

Self-fertilization

Female gamete is fertilized by a male gamete from the same plant.

Hybridization

To breed two plants with different characters.

Cross fertilization

The union of female and male gametes from different individuals.

Male gametes (sperm cells)

Produced within pollen grains, which are formed in structures called stamen.

Female gametes (egg cells)

Produced in ovules, which form within an ovary.

Self-fertilization

Pollen grain (sperm cell) must land on stigma, thus enabling sperm to migrate to ovule and fuse with an egg cell.

Cross-Fertilization (cross)

Pollen from one plant is placed on the stigma of a flower from a different plant.

Single-factor Cross

Experimenter follows only single a character (height).

P generation

True-breeding parents: continues to show the same trait after several generations of self-fertilization.

F1 generation

Offspring of P cross.

F2 generation

F1 self-fertilizes.

Monohybrids

Considered monohybrids if their true breeding parents (P generation) only differed in a single character.

Dwarf trait (recessive)

The trait that is maked.

Dominant

When traits are displayed, they are considered this.

3:1 ratio

the ratio that mendel discovered in the F2 generation.

Dominant

The displayed trait.

Recessive

Trait is masked by the presence of the dominant trait.

Genes

Every individual has two genes for a character.

Alleles

A gene has two variant forms, or alleles.

Segregation of alleles

Two copies of a gene carried by an F1 plant segregate (separate) from each other, so that each sperm or egg carries only one allele.

Mendel’s Law of Segregation

The two alleles of a gene separate (segregate) from each other during the process that gives rise to gametes, so that every gamete has one allele.

Genotype

The genetic composition of an individual.

Homozygous

Two identical alleles of a gene (TT & tt).

Heterozygous

Two different alleles of a gene (Tt).

Phenotype

The physical or behavioral characteristics that are the result of gene expression.

Punnett square

Possible combinations of sperm and egg can be shown using a to predict the results of a genetic cross between individuals of known genetic makeup.

Testcross

Breed the dominant individual with a recessive homozygote

Two-Factor Cross (Dihybrid cross)

Follows inheritance of two different characters.

Two genes are linked

Variants found together in parents are always inherited as a unit.

Two genes are independent

Variants are randomly distributed.

Mendel’s Law of Independent Assortment

Alleles of different genes assort independently of each other during gamete formation.

Chromosome Theory of Inheritance

Chromosomes contain the genetic material (DNA).

Mendel’s Law of Segregation

The pairing and segregation of homologous chromosomes during meiosis is responsible for this.

gene’s locus

The physical location of a gene on a chromosome.

Law of Independent Assortment

Random alignment of chromosome pairs during meiosis I leads to the independent assortment of genes found on different chromosomes.

Carriers

Heterozygous individuals who carry the recessive allele but are phenotypically normal.

Pedigree analysis

Inherited trait is analyzed over the course of several generations in one family.

Recessive mode of inheritance

Affected individual must inherit two copies of the mutant allele.

Sex Chromosomes

Sex chromosomes are found in many (but not all) species with two sexes.

wild-type

Morgan noted wild-type, or normal, phenotypes that were common in the fly populations.

mutant phenotypes

Traits alternative to the wild type.

sex-linked gene

A gene is located on either sex chromosome.

Y-linked genes

Genes on the Y chromosome are called this.

X-linked genes

Genes on the X chromosome are called this.

hemizygous

A male needs only one copy of the allele.

Simple Mendelian Inheritance

Recessive allele does not affect phenotype of heterozygote.

Codominance

a single individual expresses two alleles.

Multiple Alleles

In populations, most genes exist in more than two allelic forms.

Gene interaction

A single trait is controlled by two or more genes, each of which has two or more alleles.

Epistasis

A gene at one locus alters the phenotypic expression of a gene at a second locus.

Pleiotropy

One gene, multiple phonotypic effects.

Norm of reaction

Effects of environmental variation on a phenotype.

Discrete

Clearly defined phenotypic variants.

Polygenic

Multiple genes contribute to phenotype.