ch 15 Genetics and Inheritance Concepts

These flashcards cover key vocabulary and concepts related to genetics and inheritance as presented in the lecture notes.

Tay-Sachs disease

A genetic disorder caused by a mutation in the HEXA gene that leads to the destruction of nerve cells in the brain and spinal cord.

Mendel’s Law of Independent Assortment

One gene does not affect the inheritance of another gene. Genes on different chromosomes will separate during meiosis independently

Thomas Morgan Hunt

Who found the first solid evidence associating a specific gene with a specific chromosome?

Drosophila melanogastar (fruit fly)

What species did Morgan start to study?

Wild type

______ aka normal phenotypes that are common in population

Genetic recombination

_________ is the production of offspring wit combinations of traits different from either parent

Genetic map

________ is an ordered list of genetic loci along a particular chromosome

What did Strurtvant predict with the genetic map?

The farther part two genes are, the higher probability that a crossover will occur between them aka the higher the recombination frequency

Linkage map

_______ is a genetic map of chromosomes based on recombination frequencies

Map units

Distance between genes can be expressed as ______

1% recombination frequency

What does one map unit represent on a linkage map?

Separated/unlinked

What does it mean if there are at least 50 map units between two genes?

Turner syndrome (X)

What condition is a result of having only one sex chromosome: X0

Klinefelter Syndrome

What condition is a result of having an extra X chromosome (XXY)

Jacob’s Syndrome (super males)

What condition is a result of an extra Y chromosome (XYY)

Meta females

What is the condition of having three X chromosomes?

Polyploidy

What condition in which an organism has more than two complete sets of chromosomes such as triploidy (3n) and tetraploidy (4n)

What is polyploidy common in?

Plants

Breakage of a chromosome can lead to four types of changes in a chromosome:

Deletion, duplication, inversion, translocation

Deletion

_____ is the removal of a chromosomal fragment

Duplication

______ repeats a segment on a chromosome

Inversion

______ reverses orientation of a segment within a chromosome

Translocation

______ moves a segment from one chromosome to another

cri du chat (cry of the cat)

The syndrome ______ results from a deletion in chromosome 5 that usually die early in childhood

Mitochondrial myopathy

_________ is defects in mitochondrial genes that prevents cells from making enough ATP

Methylation

______ is the addition of methyl group that binds to histones

Acetylation

______ is the addition of an acetyl group to active genes nearby to loosen up DNA to activate genes

Mutant phenotypes

______ are traits alternative to the wild type

SRY

A gene on the Y chromosome aka _____ is responsible for the development of the testes

Sex linked gene

A gene that is located on either sex chromosome is called _______

Homozygous dominant/recessive

What combination of alleles are needed for a testcross?

Autosomal recessive trait

A trait that is expressed only when two copies of the recessive allele are present.

Law of Segregation

Mendelian principle that states that each individual has two alleles for each gene and that these alleles segregate during gamete formation.

Dihybrid cross

A genetic cross between individuals that differ in two traits, examining the inheritance patterns of both.

Independent assortment

Mendel’s second law, stating that genes for different traits can segregate independently during the formation of gametes.

Genetic linkage

Tendency of alleles that are located close to each other on a chromosome to be inherited together.

X-linked inheritance

Pattern of inheritance characteristic of genes located on the X chromosome, often resulting in different patterns of disease manifestation in males and females.

Aneuploidy

A condition in which an individual has an abnormal number of chromosomes, which can lead to various genetic disorders.

Linkage map

A genetic map based on recombination frequencies that shows the relative positions of genes on a chromosome.

Barr body

The inactive X chromosome present in female mammals, which condenses to prevent gene expression.