chpater 14 - mendel and the gene idea

character

a heritable feature or trait category that can vary among individuals of a species.

trait

A varation in a character

truebreeding

Organisms which are the same as the parent

hybridization

The mating and/or crossing of true breeding varieties

p generation

The generation which comes before the f1, or better known as the parents

F1 generation

This is the offspring of the P generation

F2 generation

This is the offspring of the F1 generation

Law of segregation

2 alleles for a trait will separate during the making of gametes which leads to them being in different gametes

alleles

Alternate versions of the same gene

there will be versions of a gene per parent

dominnant allele

The allele which gives the appernace to the organism

recessive allele

This is the allele which is not shown but affects the genotype of the organism

punnet sqaure

A way to determine the probability of a geno of an organism

The dominant allele will be capital

The recessive allele will be lower case

homozygote

An organism which has the same alleles for a particular gene

homozygous

(Adjective)An organism which has the same alleles for a particular gene

heterozygous

An organism which has different alleles for a particular gene

heterozygote

(Adjective)An organism which has the same alleles for a particular gene

phenotype

This is the obverseable traits of an organism

genotype

This is the genetic makeup of an organism

testcross

The breeding between an organism with an unknown genotype and a recessive homozygote

monohybrids

A monohybrid is an organism that is heterozygous for ONE gene.

monohybrid cross

A monohybrid cross is a genetic cross that examines one gene (one character) at a time, usually between two individuals that are heterozygous for that gene.

dihybrids

A dihybrid is an organism that is heterozygous for TWO different genes.

dihybrid cross

A dihybrid cross is a genetic cross that tracks two genes (two characters) at the same time. Usually, both parents are heterozygous for both genes.

law of independent assortment

The Law of Independent Assortment is one of Mendel’s foundational principles of genetics. It explains how different genes are inherited independently of one another.

multiplication rule

Multiply the probabilities of each independent event.

ex:What’s the probability that a child is Aa AND Bb?

• P(Aa) = 1/2

• P(Bb) = 1/2

So:

P(Aa AND Bb)=12⋅12=14

addition rule

Add the probabilities of each event.

ex:What’s the probability a child is AA OR Aa?

• P(AA) = 1/4

• P(Aa) = 1/2

So:

P(AA OR Aa)=14+12=34

complete dominance

When an allele fully covers the other allele

incomplete dominance

When neither allele are fully domaint

codominance

When both of the alleles are present

tay sach disease

pleiotropy

Pleiotropy occurs when one gene influences multiple, seemingly unrelated traits.

The gene responsible for sickle‑cell anemia affects:

• Red blood cell shape

• Resistance to malaria

• Organ damage

• Pain episodes

One gene → many effects.

Epistasis

Epistasis occurs when one gene affects or masks the expression of another gene.

In Labrador retrievers:

• One gene determines pigment color (black vs. brown).

• Another gene determines whether pigment is even deposited in the fur.

If the deposition gene is recessive (ee), the dog is yellow, regardless of the pigment gene. So one gene controls or overrides another.

quantitative characters

charatistics where can vary in populations

polgenic inheritance

2 or more gens on a single phenotypic character

multifactorial

Influence of both genetic and environmental which affect the phenotype

pedigree

A display of a families generation which is used to find information about traits and genetype of the family

carrier

Offspring which have a recessive allele for a particular trait

cystic fibrosis

A genetic disorder affecting the CFTR gene, leading to thick, sticky mucus in the lungs and digestive tract.

huntington disease

A genetic neurodegenerative disorder caused by a mutation in the HTT gene.

amniocentesis

A prenatal test performed around 15–20 weeks of pregnancy

chorionic vilus sampling

A prenatal diagnostic test done between 10–13 weeks of pregnancy to detect genetic disorders in a fetus.