Mendelian Inheritance Flashcards
The “Father” of Genetics
Gregor Mendel
Who was Mendel?
Monk
Later an Abbot after his work was ignored by the scientific community
Beekeeper
Meterologists
Physicists
Biologist
Mathematician
Theologian
Most of the work between 1853-1856
Breeding experiments took several years just to get enough homozygous plants in order to breed
What is the The Chromosomal Theory of Inheritance?
The chromosomal theory of inheritance is the idea that genes, the units of heredity, are physical in the chromosomes
Chromosome are seen in all dividing cells and are passed from generation to generation
How are Chromosomes Arranged
One homologous of any pair is derived from one parent and its partner from the other parent
How many pairs of autosomal chromosomes are in the human genome??
22
How many pairs of sex chromosomes are there?
1
Chromosomal number of a Garden Pea
2n 14
n=7
Define Genes
Unit of DNA that transmits genetic information. Codes for a specific protein that will play a structural of functional role in the sell
Define Genotypes
sets of alleles that are present for the type.
Define phenotypes
Observable physical traits produced by the actions of one or more gene-encoded proteins
How is the F2- Second filial generation obtained?
obtained by inbreeding the F1 generation
What forms Alleles:
Mutation
The formation of different alleles is due to errors in DNA replication and can occur in mitosis or meiosis
Can be passed on if it occurs in a germ cell
Usually result in some sort of altered protein
Usually not lethal
Define recessive
the trait not expressed where the dominant form of the trait is present
Define dominant
the expressed form of the trait when present ( even if it just 1 allele)
Homozygous
both alleles are identifical
Heterozygous
two different alleles are non-identical
What are Mendel’s ratios:
3:1
What is Laws of Dominance
F1 generation always showed the dominant trait
What is a Monohybrid crosses
Mating two of any individual with a variant in any one trait
F2- 3:1 ratio
What’s Mendel’s Recurring Ratios
F2 generation ratio was consistent
What’s Dihybrid
looks at two traits at one time
Ratio 9:3:3:1
What is Segregation
During meiosis, alleles segregate
Homologous chromosomes separate
Each allele for a trait is packaged into a separate gamete
What is Independent Assortment
Alleles for 1 trait sort into gametes independently of the alleles for a 2nd trait
Who is credited with first proposing the chrome theory of inheritance
Walter Sutton
What is Gene Linkage
is the tendency of alleles that ae close together on a chromosome to be inherited together during the meiosis phase of sexual reproduction
Violates Mendel’s law of independent assortment
_________ violates Mendel’s law on dominance
Incomplete dominance
_________occurs when both characteristics are expressed
Codominance
What is Pleitrophy
one allele can have an effect on more than one trait
eg Sickle Cell Anemia
What is Epistasis
One allele can influence the expression of a different allele
