CALM 4 Flashcards
basic units of heredity, which is the transmission of inherited traits.
genes
A gene is the long ____molecule of which that transmits information, in its sequence of four types of building blocks
deoxyribonucleic acid (DNA)
Was the first to probe the underlying rules of inheritance of specific traits.
Gregor Mendel
Mendel described units of inheritance that pass traits from generation to generation and called them _____” (which would be later on renamed to genes by English embryologist William Bateson).
elementen
Alternate forms of a gene are called___
alleles.
Each reproductive cell (or gamete) produced by a plant contains only ___copy of a gene for each trait.
one
Even though the pair of alleles that governed a trait remained together throughout the life of an individual plant, they became separated (or segregated) from one another during the formation of gametes.
This formed the basis of Mendel’s First Law: Law of Segregation.
The segregation of the pair of alleles for one trait had no effect on the segregation of alleles for another trait. A particular gamete could receive a paternal gene governing seed color and a maternal gene governing seed shape.
This formed the basis of Mendel’s Second Law: Law of Independent Assortment
Father of Genetics.
Gregor Mendel,
Classified based on the probability of a plant, animals or humans.
Most common traits that occurred in the generations.
dominant
Rare type or sometimes no appearance at all.
Appeared in a low ratio compared to the dominant.
recessive
One trait that masks another is said to be __- ; the masked trait is ___
dominant ;recessive.
one trait is followed and the parents are hybrids, this is called a
monohybrid cross.
Paired sets of genes separate as gametes form then combine anew when gametes join at fertilization.
MENDELIAN LAWS:
each gene was packaged in a separate gamete
LAW OF SEGREGATION
An individual with two identical alleles for a gene is ___for that gene.
homozygous
An individual with two different alleles is heterozygous – or what Mendel called ____
“non-true-breeding” or “hybrid”.
describes the organism’s alleles
genotype
describes the outward expression of an allele combination.
phenotype
most common expression of a particular allele combination in a population.
wild type phenotype
variant of a gene’s expression that arises when the gene undergoes a change, or mutation.
mutant phenotype
Illustrates how alleles combine in offspring.
The different types of gametes are listed along two sides of the square.
punnett square
Crossing an individual of unknown genotype with a homozygous recessive individual
test cross
Inheritance of single genes
Mendelian, or monofactorial, inheritance.
A second gene on chromosome 15 or ___the is responsible for controlling the expression of the
HERC2 gene ; OCA2 gene.
rules that explain the common patterns of single-gene transmission which makes it possible to calculate the probability that a particular couple will have a child who inherits a particular condition.
Modes of Inheritance
Shows that a trait can appear in either sex because an autosome carries the gene.
AUTOSOMAL DOMINANT INHERITANCE
___ traits do not skip generations.
autosomal dominant
Males and Females transmit the trait with equal frequency.
autosomal dominant
Is an example of an autosomal dominant condition, caused by a single dominant allele which means that heterozygous individuals will develop the disease.
Huntington’s disease
said to be a rare and fatal inherited disease of the central nervous system (Figure 4.9) causing damage to brain cells, leading to a gradual loss of coordination, decline in mental ability and changes in personality
Huntington’s chorea
Shows that a trait can appear in either sex.
AUTOSOMAL RECESSIVE INHERITANCE
The trait can skip generations.
AUTOSOMAL RECESSIVE INHERITANCE
follows the inheritance of 2 different traits, each from a gene with 2 different alleles.
Law of Segregation
states that for two genes on different chromosomes, the inheritance of one does not influence the chance of inheriting the other.
LAW OF INDEPENDENT ASSORTMENT
Display family relationships and depict which relatives have specific phenotypes and genotypes.
Pedigree Charts
autosomal recessive inherited disorder.
albinism
arise when families are small and the trait is not severe enough to impair fertility.
Inconclusive pedigrees
A genotype (allele combination) that causes death is, by definition,
lethal.
it causes death before the individual can reproduce, which prevents passage of genes to the next generation.
lethal allele
causing neuron degeneration in the brain and spinal cord, is lethal by age 3 or 4.
Tay-Sachs
may not be lethal until late middle age.
Huntington’s disease
Early acting lethal alleles in humans cause
spontaneous abortion.
or long trunk and short limbs is also a lethal genotype in humans.
Achondroplastic dwarfism
A gene can exist in more than two allelic forms in a population because it can mutate in many ways wherein the sequence of hundreds of DNA bases that make up a gene can be altered in many ways.
MULTIPLE ALLELE COMBINATIONS
too little or lack of an enzyme causes the a.a. phenylalanine to build up in brain cells resulting to hundreds of mutant alleles pair to cause 4 basic phenotypes
Phenylketonuria (PKU)
wherein one genotype experiences frequent, severe respiratory infections, congested lungs, and poor weight gain while another genotype experiences frequent bronchitis and pneumonia.
Cystic Fibrosis
where one allele is expressed, while the other isn’t.
Complete Dominance
where the heterozygous phenotype is intermediate between that of either homozygote.
Incomplete Dominance
where different alleles are both expressed in a heterozygote.
co-dominance
determined by polysaccharides present on the surface of RBCs.
ABO Blood Group
A phenotypic class does not survive to reproduce.
lethal allele
Many variants or degrees of a phenotype occur.
multiple allele
A heterozygote’s phenotype is intermediate between those of two homozygotes.
incomplete dominance
A heterozygote’s phenotype is distinct from and not intermediate between those of the two homozygotes.
co dominance
One gene masks or otherwise affects another’s phenotype.
epiptasis
Some individuals with a particular genotype do not have the associated phenotype.
penetrance
A genotype is associated with a phenotype of varying intensity.
expressivity
The phenotype includes many symptoms, with different subsets in different individuals.
pleiotrophy
An environmentally caused condition has symptoms and a recurrence pattern similar to those of a known inherited trait.
phenocopy
Different genotypes are associated with the same phenotype.
Genetic Heterogeneity
The ___mitochondrial genes encode tRNA, rRNA, or proteins involved in protein synthesis or energy reactions.
37
depict linked genes. Researchers can examine a group of known linked DNA sequences (a haplotype) to follow the inheritance of certain chromosomes.
linkage maps
