d3.2 inheritance Flashcards
monohybrid influence
only one trait
in the same pair of chromosomes (alleles)
diff version of the alleles
2 alleles
determine what the characteristic should be
single-nucleotide polymorphism
can cause different alleles in the gene pool
single nucleotide polymorphism eg
blood type
genotype
alleles responsible for the characteristics
eg. BB
phenotype
characteristic expressed due to the alleles in the dna and the environment
discrete variations
either this or that
discrete variations eg
male or female
dominant
- usually the dominant allele codes for a protein that is active and carries out a function
- always expressed in the offspring
co-dominant
pair of alleles are both expressed
homozygous
alleles for the characteristics are the same
eg. BB
heterozygous
alleles for the characteristic are different
eg. Bb
how to figure out genotype
cross with homozygous recessive organism
1:1 = heterozygous dominant
1:3 = 2 heterozygous
recessive
- usually the recessive allele code for a non-functional protein
- may not be expressed in the offspring
allele
different versions of genes that contain information for the same characteristics
eg. eye colour
chromosome
made of dna and protein (histone) and contains genes
genes
heritable factors that control specific characteristics
gene locus
specific position of a gene on a chromosome
homologous
same loci same gene
how to say location of gene locus
chromosome number
p- short arm
q- long arm
number- bands away from the centromere
autosomal recessive disorder
not on the chromosome that determines gender
autosomal dominant disorder
achondroplastic dwarfism
sex linked recessive eg
haemophilia
- x linked
haemophilia
cant make clotting factor VIII so cant clot their blood properly
pedigree chart
circle- females
square- males
no carriers- dominant
phenylketonuria PKU
mis-sense mutation in the gene that produce styrosine hydrogenate- phenylalanine cant be converted to tyrosine
= results in developmental problems and seizures
recessive + autosomal eg
phenylketonuria PKU
mis-sense nutation
base substitution where the change in a single base results in a different amino acid being produced in the amino acid
single nucleotide polymorphism
variation at a single nucleotide in the genome could lead to different amino acids and multiple alleles in the gene pool
eg. blood group
gene pool
can look at the frequency of alleles represented in the reproductive population
why blood groups are different
different antigens on the surface of the red blood cell
why blood type needs to match
if detected as a foreign by immune system and attacks → group them tgt → form blood clot → die
incomplete dominance eg
4 o’clock flower
intermediate phenotype
expressing a mixture of the phenotypes of the parents
phenotypic plasticity
traits developed can be influenced by the environment through different gene expressions
polygenic inheritance
trait is affected by more than one gene
polygenic inheritance eg
skin colour
unlinked genes
genes that are not on the same chromosome
independent assortment
alleles of two different genes are passed into gametes without influencing each other (as long as the genes are located on different chromosomes)
gene linkage
linked genes are pairs or groups or gene which are inherited together, carried on the same chromosome
when does independent assortment not occur
between linked genes
