Genes and Inheritance lectures Flashcards
gene
unit of heredity, carrying information for a single polypeptide or RNA
gamete
a mature reproductive cell
allele
a variant of a genetic character at a given locus on a chromosome
Mendel’s rule of independent assortment
alleles of different genes assort independently
monotypic nature of the phenotype
controlled by two alleles (dominant and recessive)
only one ‘visible’
dihybrid
cross with two genes
recombinant phenotypes
different from either parent
recombination through meiosis
whole chromatids
crossing over of chromatids
part of chromatid
what does recombination frequency tell us?
how far apart the genes are
what is recombination frequency measured in?
cM (centiMorgans) or genetic map units
how many base pairs of DNA is 1cM?
1,000,000
recombination frequency
((number of recombinants)/(total number of progeny))
X 100
haplotype
a group of genes inherited together from a single parent
Labradors’ example
what are the names of the proteins for black and brown fur?
DHI-melanin = dark brown-black DHICA-melanin = brown
Labradors’ example
what does Tyrosinase-related protein 1 do?
participates in conversion of a darker eumelanin (black) to lighter (brown)
Labradors’ example
what colour of fur do homozygous carriers of mutant Trp1 turn?
brown
Which gene codes for Tyrosinase-related protein 1?
Trp1 (Tryp) gene
What is the Labrador’s example about?
Fur colour
What is Agouti?
A specific colouring of fur?
Is the allele for Agouti in the Agouti mouse dominant or recessive?
dominant
How does Agouti fur come about?
by introducing a band of yellow colour resulting from deposition of phaeomelanin (yellow pigment) on dark hair)
What does loss of function of the Tyr gene cause?
no melanin -> albino
what pattern results if there are no melanocytes present in certain areas?
spotting pattern
Kit gene