Mendelian Genetics Flashcards
What is a gene?
Discrete hereditary unit of information
What is the locus?
The position of a gene on a chromosome
What is an allele?
A different version of the same gene
What does homozygous mean?
A diploid organism pair of identical alleles
What does heterozygous mean?
A diploid organism pair of different alleles
What is the phenotype?
The physical appearence
What is the genotype?
Genetic composition
How did Mendel choose the organisms?
Short life cycle, large number offspring, many varieties of them, controlled matings, either or characteristics
What is a character?
A feature that varies
What are traits?
The variations of the feature
What is a true breeding strain?
A trait thats unchanged over several generations from self fertilisation
What does Monohybrid crossing mean?
Analyses only one character - flower colour
What is Mendels first law?
Allele segregation
First law of segregation involves….
Meiosis - chromosomes duplicate, homologous chromosomes seperate - then they split so there is 4 sister chromatids
Are the genotype and phenotype ratios different?
Yes as a dominant recessive are the same as dominant dominant traits.
What is a testcross?
Consider the phenotype - dominant purple - could be PP or Pp how do we work this out - If its PP all will be purple if its Pp 50:50
What is a dihybrid cross?
Examine two characteristics simultaneously
Examples of dihybrid?
Shape and Colour? They have 4 alleles essentially
Dihybrid colour how does it work?
Same letter for different colours - yellow is dominant letter green is recessive letter
Dihybrid Shape how does it work?
Same letter for different shapes - Wrinkled is recessive, round is dominant
What would be yellow and round?
YYRR
When is the acroynm FOIL used?
When crossing the F1 generation in a dihybrid to find the F2 generation
What are some human mendelian traits?
Albinism, Colour blindness, Cystic Fibrosis, Huntingtons, Acrochondrodysplasia, Widows peak
What shape is the male in a pedigree tree?
Square
