Genes, Chromosomes, and Human Genetics

Flashcards covering key vocabulary terms related to genes, chromosomes, human genetics, and inheritance patterns.

Progeria

A genetic disease that causes premature aging due to an error in the gene for lamin A.

Drosophila melanogaster (Fruit Fly)

A model organism used in genetics, first cultivated by Thomas Hunt Morgan, that contributed to many important biological discoveries.

Gene Linkage

The physical association of genes on the same chromosome.

Genetic Recombination

A process in which homologous chromosomes exchange segments with each other during meiosis.

Recombination Frequency

The percentage of testcross progeny that are recombinants, used to determine the distance between two genes on a chromosome.

Map Unit (mu) or Centimorgan (cM)

A unit equivalent to a recombination frequency of 1%, used in linkage mapping.

Mode of Inheritance

Patterns with which a mutant phenotype is associated, including autosomal recessive, autosomal dominant, X-linked recessive, X-linked dominant, Y-linked, and mitochondrial.

Pedigree Analysis

A method used to track inheritance patterns in families.

Human Autosomal Traits

Traits located on non-sex chromosomes (1-22).

Sex-linked Genes

Traits located on the sex chromosomes.

Autosomes

Chromosomes other than the sex chromosomes.

Females

The homogametic sex (XX) that produce only one type of gamete (X).

Males

The heterogametic sex (XY) that produce two types of gametes (X and Y).

Sex Linkage

The inheritance pattern of alleles carried on the sex chromosomes.

X-linked Recessive Traits

Traits caused by recessive alleles on the X chromosome that appear more frequently among males.

X Chromosome Inactivation

A dosage compensation mechanism in females that inactivates one of the two X chromosomes in most body cells.

Chromosomal Mutations

Changes in chromosome structure or chromosome number.

Deletion

A segment is lost from a chromosome.

Duplication

A segment is broken from one chromosome and inserted into its homolog, adding to the ones already there.

Translocation

A segment is attached to a different, nonhomologous chromosome.

Inversion

A segment reattaches to the same chromosome, but in reversed orientation.

Nondisjunction

The failure of homologous pairs to separate during the first meiotic division or of chromatids to separate during the second meiotic division.

Aneuploids

Individuals with extra or missing chromosomes.

Euploids

Individuals with a normal set of chromosomes.

Trisomy 21

Having an extra copy of chromosome 21, leading to Down syndrome.