Genetics Flashcards
believed that reproduction of organisms originate through formation of miniature versions known as homunculus
preformationism
who and when was preformationism established
17th century by pythagoras and aristotle
each part of the body can produce ____________ that contribute to the formation of an offspring
gemmules
where did the idea of preformationism originate from?
parthenogenesis of insects, amphibians, and reptiles
sperm contains the miniature individual and only nourished by the ovum
spermists
thought the same and that the seminal fluid only stimulates it
ovists
criticized aristotle’s work by asserting “ex ovo omnia” - stating that all organisms come from eggs
william harvey (epigenesis)
organs of an organism that is frequently and continuously used becomes more developed and prominent
theory of use and misuse
modifications that an organism underwent in its life is due to the factors of use and misuse and will be preserved and passed on to the next generation
theory of acquired characteristics
there will be changes in the characteristics of organisms due to pressure exerted by the environment
theory of evolution and natural selection
2 types of cells in the body proposed by august weismann
autosomal or somatic cells, gametes
theory by august weismann that suggests there are 2 types of cells in the body
germplasm theory
cells that are responsible for sustaining the body
autosomal or somatic cells
cells that contain hereditary information
gametes
he disproved the concept of preformation using mice
august weismann
process of passing on of traits from parents to offspring through sexual or asexual reproduction
heredity or inheritance
presence of different frequencies of traits among individuals or populations
variation
expressed characteristics of an individual
phenotype or traits
set of information from the DNA that encodes for specific traits
genotype or genes
an organism’s complete set of genes
genome
contains bundles of tightly coiled DNA located in the nucleus
chromosome
subunit of 2 chromosomes where 2 turns of DNA is wrapped around a set of 8 proteins called histones
nucleosome
self-replicating macromolecule present in every living organism
DNA
activated variant of a gene
dominant trait
inactivated variant of a gene
recessive trait
only one allele is inherited from each of the parent since chromosomes split during meiosis
law of segregation
genes of different traits do not accect other genes
law of independent assortment
traits that come from chromosome 1 to 22
autosomal traits
traits that come from chromosome x and y
sex-linked traits
test-cross that can produce offspring
parental generation
result of any parental cross
filial generation
both alleles have the same expression
homozygous
alleles have different expressions
heterozygous
different expressions of genes due to different interplay between genes
genetic interactions
occurs when one allele is expressed in the phenotype by masking the recessive allele
complete dominance
occurs when the expression of the recessive gene is not completely masked
incomplete dominance
occurs when the expression of genes lacks dominance and recessiveness
co-dominance
occurs when the expression of genes exceeds measurement
over-dominance
complete dominance at gene pairs
novel phenotype
complete dominance but recessive is epistatic
recessive epistasis
complete dominance but dominant is epistatic
dominant epistasis
at least one allele of each gene is dominant
complimentary epistasis
at least one dominant presence in any gene
duplicate gene
