Topic 12.1: Nomenclature Flashcards
what is genotype
the genetic make up
the DNA sequence of an organism or individual which determines the specific characteristics (phenotype) of that organism or person
what is phenotype
the characteristics
an organism’s observable physical and biochemical characteristics directly influenced by the genotype and/or environment. the observed signs and symptoms of a condition
how many copies of each gene do each individual ahve
2
how many alleles of a gene does a person have
2
what is a gene
a stretch of DNA sequence at a specific chromosomal location that carries the code for a polypeptide or untranslated RNA (plus regulatory sequences)
what is an allele
a version or variant of a gene
what are the genes like in homologous chromosomes
homologous chromosomes have the same genes but may carry different alleles
what are the genes like in sister chromatids
sister chromatids have identical DNA and the same alleles
what are the genes like in non-sister chromatids
they have the same genes but may have different alleles
what does homozygous mean
two alleles of a gene are the same
individual is known as homozygote
what does heterozygous mean
two alleles of a gene are different
individual is known as heterozygote
what does hemizygous mean
only one allele of a gene on the X chromsome
what does dominant mean
the dominant allele in a heterozygote determines the phenotype
what does recessive mean
the non dominant allele in a heterozygote
what does co dominant mean
neither allele in a heterozygote is dominant and the phenotype is new (different from phenotypes determined by either allele)
where is the gene located for human bloody types and what does it code for
on chromosome 9 and codes for glycoproteins on the surface of red blood cells
how is the gene for blood types often written as
I
what are the different alleles for blood type
A, B and O or I^A, I^B, I^O
alleles A and B are dominant over O
alleles A and B are co dominant
what are the 4 phenotypes for blood types
A, B, AB, O
what are the genotypes for blood group A
I^A I^A
OR
I^A I^O
what are the genotypes for blood group B
I^B I^B
OR
I^B I^O
what are the genotypes for blood group AB
I^A I^B
what are the genotypes for blood group O
I^O I^O
what are the symbols for pedigree analysis
male = square
female = circle
affected = filled in
heterozygote = half filled
carrier female = outer white circle and black dot in middle
unknown sex = diamond
deceased = line through symbol
same kinship = two lines between square and circle
married = one line between square and circle
monozygotic twins = two circle attached with triangle and inner triangle
dizygotic twins = two circles attached with triangle
two diagonal lines through relationship = divorce
square with D = donor
generations with roman numerals, and number of birth is another number
what are important features of pedigree analysis
every generation on separate line
label every generation with roman numerals, top to bottom
males left and females right in relationship where possible
siblings in age order, from left to right
label every individual of every generation with numbers, left to right
shading indicates phenotype
