Unit 2 - AOS 1 Flashcards
Epigenetics
the study of factors that influence the regulation or expression of genes that do not involve changes to the DNA itself.
genotype
The genotype of an organism is the set of alleles present in an organism. (written in allele format eg. Aa)
phenotype
Phenotype is the physical appearance of an organism – an observable characteristic.
(written with adjective words eg. red hair)
allele
An allele is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location.
mutations
A mutation is a change in the DNA sequence of an organism. Mutations can result from errors in DNA replication during cell division.
traits
specific characteristics and features of an individual.
complete dominance
One allele fully masks the effect of the other, displaying the dominant trait. (A or B bloodtype)
incomplete dominance
Heterozygous phenotype is a blend of both alleles, neither fully dominant nor recessive. (AB bloodtype)
codominance
Both alleles in a heterozygous genotype are fully expressed, leading to distinct, simultaneous phenotypic traits.
tyrosinase (melanin)
an enzyme crucial for melanin production, which determines skin, hair and eye colour.
monohybrid crosses
the hybrid of two individuals with homozygous genotypes which result in the opposite phenotype for a certain genetic trait.
gene linkage
DNA sequences that are close together on a chromosome to be inherited together during meiosis
sex-linkage
Sex linkage applies to genes that are located on the sex chromosomes and its inheritance through members.
y-linked
characteristics or traits that are influenced by genes on the Y chromosome only, and therefore is only passed onto males, since they posses a y chromosome.
x-linked
characteristics or traits that are influenced by genes on the X chromosome.
autosome
any chromosome that is not a sex chromosome.
loci
The location of a specific gene on a chromosome
carrier
an individual who carries the recessive trait, however it is masked by the dominant allele, therefore they are not affected.
crossing over
the exchange of DNA between paired homologous chromosomes in the prophase I of meiosis.
dihybrid crosses
A dihybrid cross can investigate two characteristics and its possibilities (eg. skin colour and eye colour)
hemizygous
Non-matching pair of chromosomes, with different alleles, shape length, and banding patters (eg. XY chromosomes)
homozygous
matching pair of chromosomes, with identical alleles, length and banding patterns.
heterozygous
pairs of chromosomes, with the same length and size, however different alleles.
mendels law
- Law of Segregation:
Parents pass on one version of each gene to their offspring. - Law of Independent Assortment:
Different genes are inherited independently of each other. so one trait does not affect the inheritance of another trait.
