Chromosomal Inheritance and Genetic Linkage

These flashcards cover key vocabulary and concepts related to chromosomal inheritance, genetic linkage, and associated genetic disorders.

Genetic Linkage

When genes are located close together on the same chromosome and tend to be inherited together.

Linked Genes

Genes that are found close together on the same chromosome and do not assort independently.

Recombination Frequency

The percentage of recombinant offspring produced in a genetic cross, used to determine genetic linkage.

Thomas Hunt Morgan

An American geneticist who demonstrated the concept of genetic linkage through experiments with fruit flies.

Drosophila

A genus of small flies, commonly known as fruit flies, used by Morgan in genetic experiments.

Independent Assortment

Mendel's principle stating that alleles of different genes assort independently of one another during gamete formation.

Mosaicism

A condition in which individuals have two or more genetically different cell lines in their bodies.

Nondisjunction

An error during cell division that results in abnormal chromosome numbers in gametes.

Aneuploidy

A condition in which there is an abnormal number of chromosomes, leading to genetic disorders.

Polyploidy

A condition in which an organism has more than two complete sets of chromosomes.

Crossing Over

A process during meiosis where homologous chromosomes exchange segments, leading to recombination.

Centimorgan

A unit of measure for genetic linkage, equating to a 1% chance of recombination occurring between two loci.

Chromosome

A long DNA molecule containing genetic information; humans have 23 pairs.

Gene

A segment of DNA that encodes a protein or RNA molecule.

Phenotype

The observable characteristics or traits of an organism.

Genotype

The genetic constitution of an individual, often in reference to a specific trait.

X chromosome

One of the two sex chromosomes; females have two X chromosomes while males have one.

Y chromosome

The sex chromosome that determines male biological sex; present only in males.

Recombinant Offspring

Offspring with new combinations of traits, resulting from crossing over during meiosis.

Parental Types

Offspring that have phenotypes that match either of the parental phenotypes.

Testcross

A genetic cross between an organism with an unknown genotype and a recessive homozygote.

Mutant Alleles

Variants of a gene that result in altered phenotype or function.

Mendel's Peas

The plant model used by Gregor Mendel to establish the basic principles of inheritance.

Law of Segregation

Mendel's law stating that the two alleles for each gene separate during gamete formation.

Law of Independent Assortment

Mendel's law stating that alleles of different genes assort independently of one another.

Mitochondrial DNA

The genetic material found in mitochondria, inherited maternally.

Chloroplast DNA

The genetic material found in chloroplasts, typically inherited from the mother in plants.

Chromosomal Abnormalities

Alterations in chromosome structure or number that can affect an organism’s traits.

Deletion

A chromosomal segment is removed from the chromosome.

Duplication

A chromosomal segment is duplicated, leading to multiple copies on the chromosome.

Inversion

A chromosomal segment is reversed end to end.

Translocation

A segment of one chromosome is transferred to another nonhomologous chromosome.

Cri du Chat Syndrome

A genetic disorder caused by a deletion on chromosome 5, characterized by a distinctive cry in infants.

Down Syndrome

A genetic condition caused by trisomy of chromosome 21, leading to various developmental delays.

Klinefelter Syndrome

A genetic condition in males characterized by the presence of an extra X chromosome (XXY).

Turner Syndrome

A genetic condition in females resulting from a missing or incomplete X chromosome (X0).

Jacob's Syndrome

A genetic condition in males caused by the presence of an extra Y chromosome (XYY).

Institutional Induction

The process by which gene loci are positioned based on recombination frequencies.

Genetic Map

An ordered list of the genetic loci along a particular chromosome.

Linkage Map

A representation of the distances between genes on a chromosome based on recombination frequencies.

Recombinant Types

Offspring that show new combinations of traits due to crossing over.

Frequency of Recombination

The proportion of offspring that are recombinants compared to the total number of offspring.

X-Inactive Specific Transcript (XIST)

A gene that plays a critical role in the inactivation of one X chromosome in females.