Not-so-Simple Inheritance Patterns - WordPress.com · Inheritance • 2 alleles • 2 phenotypes...

Not-so-Simple

Inheritance

Patterns

Remember…

• Genes are

sections of a

chromosome

that have coded

instructions for

making proteins.

• Alleles are

different forms of

a gene.

Simple

Inheritance

• 2 alleles

• 2 phenotypes

• One allele is

dominant

• The other allele is

recessive

• The DOMINANT allele

completely masks the

recessive allele

Mendel Got Lucky

• In many ways Gregor

Mendel was quite lucky

in discovering his 4

genetic laws.

• He happened to use

pea plants.

• Things in nature aren’t

always so simple.

Not-so-Simple Inheritance

• 4 Main Types

– Codominance

– Incomplete Dominance

– Multiple Alleles

– Polygenic Traits

Codominance

• “Co” means together!

• Codominance = two alleles are dominant together.

• This produces a third heterozygous phenotype where BOTH traits are expressed TOGETHER

• Ex: Human Blood Type – A

– AB

Red Cow x White Cow Roan Cow

Roan cattle have both red and white hairs mixed in together!

Codominance

red x white red & white spotted

Incomplete Dominance

• Incomplete

Dominance =

neither of the two

alleles is

completely

dominant

• This produces a

third heterozygous

phenotype where

the traits are

BLENDED.

Amel & Ultra are incompletely

dominant to each other.

Amel x Ultra Ultramel

Incomplete Dominance

red flower x white flower PINK flower

Multiple Alleles

• Any of a set of three or more alleles.

• Only two of alleles can be present in a diploid organism.

• Examples:

– Human Blood Type

– Human skin, hair, and eye colors

Polygenic Traits • Result of the interaction of several genes

• Human skin, hair, and eye color

– Influenced by more than one gene at different

locations on the chromosomes

• Human Blood Pressure

– Not just 1 “blood pressure” gene with several alleles

– Caused by several genes that control other traits such

as weight, cholesterol level, kidney function, etc…

• Human Height

– The combined size of all of the body parts from head

to foot determines the height of an individual.

Role of Environment • Our environment also plays a key role in

how traits are expressed.

• Genes can be turned on/off due to

external environmental factors.

• Examples:

– Stress

– Nutrition

– Chemical exposure

– Light

– Temperature

Example of Environmental

Influence

• Human Height is heavily influenced by

hormones produced in the pituitary gland

and our diet during childhood and puberty.

• Usually, about 10% of an individual's

height is due to the environment.

Not-so-Simple Inheritance Patterns - WordPress.com · Inheritance • 2 alleles • 2 phenotypes...

Documents

There is no dominant allele, There is no recessive allele. Both alleles “blend” to result in a third phenotype

Beyond Mendelian Inheritance INCOMPLETE DOMINANCE -NEITHER ALLELE IS COMPLETELY DOMINANT OVER THE OTHER -THE HETEROZYGOUS PHENOTYPE IS A BLENDING OF

Patterns of Inheritance. I. Simple inheritance (Mendelian inheritance) One gene controls the trait There are two versions (alleles) of the gene One allele

Incomplete Dominance Codominance In a nutshell!. Review: Dominant/Recessive One allele is dominant over the other (capable of masking the recessive allele)

Genetics · 5/12/2014 · Dominant vs. Recessive •A dominant allele is one that whose phenotype will ALWAYS be expressed if you have the dominant allele. (shown as a CAPITAL LETTER)

4.3 Theoretical genetics. 4.3 Theoretical genetics: Objectives 1- Define genotype, phenotype, dominant allele, recessive allele, codominant alleles, locus,

Mendel explained how a dominant allele can mask the ... · Mendel explained how a dominant allele can mask the presence of a recessive allele. Section 2: Mendelian Genetics K What

Mendel explained how a dominant allele can mask …ddamm.weebly.com/uploads/1/3/9/8/13981972/bio_10.2_medelian... · Mendel explained how a dominant allele can mask the ... • Gregor

Complex Inheritance. Mendelian Genetics Mendel dealt with simple inheritance…dominant vs. recessive Dominant traits only require one dominant allele to

Inheritance of the colour of eyes in humans and the ...slowacki.kielce.eu/IB/NToborek.pdf · Generally, the brown allele is dominant over both blue and green ones. For example when

Example Of Multiple Allele Inheritance self

11.3 Other Patterns of Inheritance Genes can act in various ways 1.Dominant vs. Recessive – one allele completely covers another allele. 2.Incomplete Dominance

More Punnett squares. Complete Dominance Involves dominant and recessive alleles dominant allele always overpowers the recessive allele in appearance

Weeblyiheartbio.weebly.com/uploads/1/3/4/2/13422000/4.3... · Web view1. The allele for brown hair (B) is dominant to the allele for blond hair (b). The diagram shows the inheritance

Web view(a)The inheritance of the ability to produce hydrogen cyanide is controlled by two genes which are located on different chromosomes. The dominant allele of one gene,

genetics - fd.valenciacollege.edufd.valenciacollege.edu/file/sclark/Genetics (14-18).pdfgenetics terminology . . . allele - alternative form of a gene dominant allele - always expresses

Inheritance of Autosomal Dominant and Xlinked

GENETICS VOCABULARY QUIZ 2 · GENETICS VOCABULARY QUIZ 2 Allele Dominant Allele Recessive Allele Phenotype Genotype Heterozygous/Hybrid Homozygous/Purbred 1. 2 Allele Allele- one

Genetics. Incomplete Dominance Where neither the dominant or recessive allele is truly dominant over the other, both are dominant

Final Concepts for Chapter 11 Mendelian Genetics Allele Allele Dominant Dominant Recessive Recessive P-generation P-generation F1 generation F1 generation