CH 5 - Extensions & Modifications of Basic Principles I

These flashcards cover key vocabulary terms and concepts related to genetics, focusing on extensions and modifications of basic principles as discussed in the lecture.

Single Gene Expression

The expression of a trait that is determined by a single gene.

Gene Interaction

The phenomenon where multiple genes influence the expression of a single trait.

Influence of Sex

How genetic expression may differ between sexes due to sex chromosomes or sex-linked traits.

Complete Dominance

A form of dominance where the phenotype of the heterozygote is indistinguishable from that of the homozygous dominant.

Incomplete Dominance

A form of dominance where the phenotype of the heterozygote is a blend between the phenotypes of both homozygotes.

Codominance

A form of inheritance where both alleles in a heterozygote are fully expressed.

Penetrance

The proportion of individuals with a specific genotype who express the expected phenotype.

Expressivity

The degree to which a trait is expressed in an individual.

Multiple Alleles

The presence of three or more alleles at a given locus.

Lethal Alleles

Alleles that can cause death to an organism at an early developmental stage.

Epistasis

A genetic interaction where the effect of one gene is masked or modified by another gene.

Pleiotropy

A single gene that influences multiple traits.

Polygenic Inheritance

Inheritance pattern where multiple genes govern a trait, leading to continuous variation.

Sex-Linked Characteristics

Traits controlled by genes found on the sex chromosomes.

Sex-Influenced Characteristics

Traits where the phenotype is influenced by the sex of the individual.

Sex-Limited Characteristics

Traits that are only expressed in one sex despite both sexes carrying the genotype.

Genetic Maternal Effect

The phenomenon where the mother's genotype determines the phenotype of the offspring.

Cytoplasmic Inheritance

Inheritance of genes that occur outside the nucleus, typically through maternal inheritance.

Genomic Imprinting

The differential expression of a gene depending on whether it is inherited from the mother or father.

Cancer Risk Alleles

Alleles that may increase the risk of developing cancer but do not guarantee it.

Fanconi Anemia

A condition caused by inheriting two BRCA alleles, which is embryonically lethal.

Right-Coil Phenotype

The coiling phenotype seen in offspring controlled by the maternal genotype in Linnaea snails.

Mitochondrial DNA

The DNA present in mitochondria, usually inherited maternally.

Egg Cytoplasm

The cytoplasm of an egg that influences the development of the embryo.

Temperature-Sensitive Alleles

Alleles that are only functional at certain temperatures.

Himalayan Rabbit

A fur color phenotype determined by alleles of the C-locus in rabbits.

Albinism in Snails

A trait that can result from epistasis or interactions between genes affecting pigmentation.

BRCA Allele

An allele associated with increased breast and ovarian cancer risk.

Milk Production in Cattle

An example demonstrating polygenic inheritance through the accumulation of small effects.

Liger

A hybrid between a female tiger and a male lion.

Tigon

A hybrid between a female lion and a male tiger.

Hairy Ears Syndrome

A trait associated with a gene located on the Y chromosome.

Phenotypic Variation

Differences in phenotype that can result from environmental factors.

Genotype

The genetic constitution of an individual.

Phenotype

The observable physical or biochemical characteristics of an organism.

Dominance Hierarchy

A system by which alleles are ranked by their dominance over others.

Hybrid Offspring

The progeny resulting from the cross of two different strains or species.

Genetic Testing

Tests used to identify genetic disorders or predispositions.

Linkage

The tendency of genes located close to each other on a chromosome to be inherited together.

Recombination

The exchange of genetic material between homologous chromosomes during meiosis.

Pedigree Analysis

A diagrammatic method of tracking the inheritance of traits through generations.

Cumulative Characteristics

Traits that accumulate over generations, influenced by multiple genes.

Breeding Negative Traits

The potential risk of increasing negative traits through selective breeding.