Lecture 1 - Heredity Flashcards
Learn content and questions
Who is the father of Genetics?
Gregor Mendel
What type of plants did he cross to discover how traits are inherited?
Pea Plants
What type of breeding did Mendel use?
Selective Breeding
Why did Mendel use Pea plants?
- Selection Breeding is easier
- Pea plants have a rapid reproduction rate
- Pea plants produce many offspring
Define the term Gene
Fundamental units of heredity
Did Mendel state that we get one trait from our mother and one trait from our father?
Yes
Define the term Trait
A genetically determined characteristic
True or False?
Did Mendel discover that we posses recessive traits?
True
Define the term Recessive Trait?
Recessive Traits are traits that are masked by the dominant allele of the trait.
Recessive traits are only expressed phenotypically when there are two recessive allele.
Recessive traits are occur in the F2 generation
Define the term Dominant Trait?
Dominant Traits mask the recessive traits.
Dominant traits are expressed phenotypically in a homozygous and heterozygous Genotype.
Dominant traits are visible in the F1 generation.
How did Mendel explain dominant traits?
Mendel stated that the dominant trait is the trait that is physically expressed when opposites fuse (Heterozygous genotype).
An intermediate is the formed known as a Heterozygote Intermediate.
Define the term Phenotype
A phenotype is an observable/visible trait
Define the term Genotype
A Genotype is The genetic make-up of an organism that influences the Phenotype.
What is Genotype based on?
Genotype is based on Alleles NOT Genes
Define the term Segregation?
Segregation is the separation of the gene pairs during gamete formation
Can eye colour be determined?
Why?
No eye colour cannot be detemined.in an offspring
because of segregation especially if you are heterzygote
Define the term Mendelian
Mendelian inheritance in the manner in which single genes and single traits are passed down from the parent to offspring.
Name the other patterns of inheritance
- Co-dominance
- In-complete dominance
- Epistasis
- Polygenic inheritance
- Epigenentics
What are the characteristics of Co-dominance
Co-dominance is the complete expression of both alleles of a gene pair
Occurs in heterozygous
Example: AB Blood groups
What are the characteristics of Incomplete dominance?
Incomplete dominance is when one allele of a specific trait does not completely mask the other allele.
Therefore an intermediate phenotype is produced
What are the characteristics of Epistasis?
Epistasis is when one gene suppresses another gene
Do Segregation and Independent assortment occur in humans?
Yes
Are human traits are polygenic?
Yes
Define the term Polygenic
Polygenic is when one trait is influenced by more than 2 genes
Is albinism a single-gene disorder?
Yes
What are the characteristics of Albinism?
Albinism - No pigment in the skin, hair colour and eye colour
Albinism is Autosomal recessive trait
Heterozygote (Aa) parents have a 25% of having an affected child
What do we see in Random Mating?
Random mating is when we see opposites attrat
What do we see in Assortive mating
Assortive mating we see similar beings together
An example of Random mating?
In China pepople had to sniff each other to find which scent is attractive
What complex is responsible for Random mating?
The Major Histocompatibility Complex (MHC) and it is related to the immune response
Are Pedigrees are used for single gene inheritance OR single gene disorders?
Pedigrees are used for single gene inheritance and single gene disorders
What is pedigree analysis?
Pedigree analysis is a vital method used to genetically analyse genes in humans
What is a pedigree?
A pedigree is a diagram used to show the family and ancestral relationships
What is a Proband?
A proband is the affected family to first seek medical attention due to a genetic disorder
