Genes, Chromosomes, and Human Genetics

A set of flashcards covering key concepts related to genes, chromosomes, and human genetics based on the lecture notes.

What are genes?

Genes are segments of DNA that contain the instructions for the development and function of living organisms.

Linked genes

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

Recombination frequency

Recombination frequency is a measure of the likelihood that two genes will be inherited together, which is affected by the distance between them on a chromosome.

Human sex chromosomes

Human males have XY chromosomes while females have XX chromosomes.

Autosomes

Autosomes are chromosomes that are not involved in determining the sex of an individual; humans have 22 pairs of autosomes.

SRY gene

The SRY gene is located on the Y chromosome and is responsible for male sex determination.

X-inactivation

X-inactivation is the process by which one of the two X chromosomes in females is randomly inactivated to balance gene dosage between males and females.

Calico cats and X-inactivation

In calico cats, X-inactivation leads to a mosaic pattern of fur color due to two different color genes on the X chromosomes.

Chromosomal structure alteration methods

Chromosomes can alter their structure through deletion, duplication, inversion, and translocation.

Chronic myelogenous leukemia

Chronic myelogenous leukemia is caused by a specific genetic mutation that leads to the overproduction of blood cells.

Nondisjunction in meiosis

Nondisjunction during meiosis I results in gametes with an abnormal number of chromosomes, while nondisjunction during meiosis II usually involves only one pair of chromosomes.

Euploids, aneuploids, and polyploids

Euploids have the normal set of chromosomes, aneuploids have an abnormal number of chromosomes, and polyploids have more than two complete sets of chromosomes.

Down Syndrome

Down Syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 21.

Turner's syndrome

Turner's syndrome is a condition where a female has only one X chromosome (45, X), leading to developmental and reproductive issues.

Klinefelter's syndrome

Klinefelter's syndrome is a condition in males characterized by the presence of an extra X chromosome (47, XXY).

Triple X Syndrome

Triple X syndrome is a genetic condition in females where there are three X chromosomes (47, XXX), generally with mild effects.

Carrier

A carrier is an individual who possesses one copy of a gene mutation associated with a genetic disorder but does not exhibit the disease themselves.

Genetic testing in embryos

Two main ways to test for genetic conditions in embryos or fetuses are amniocentesis and chorionic villus sampling (CVS).

Cytoplasmic inheritance

Cytoplasmic inheritance refers to the transmission of genetic material found in organelles like mitochondria, which do not follow Mendelian inheritance patterns.

Genomic imprinting

Genomic imprinting is an epigenetic phenomenon where certain genes are expressed in a parent-of-origin specific manner.

Gene methylation

When genes are methylated, their expression is typically reduced, affecting how they are read and expressed.