Lecture 1a: Mendelian inheritance Flashcards
What theory: all parts of the body make seeds that are then collected and transmitted to offspring
Theory of Pangenesis (Hippocrates)
What theory: a tiny human called a homunculus (little man) in a sperm. Father entirely responsible for inheritance. Resemblence to mom comes from womb influences.
Spermists
What theory: Mom’s egg entirely responsible for inheritance. Sperm only stimulates egg to develop.
Ovists
What theory: Factors that dictate inheritance mix together from generation to generation.
Blending
Father of genetics
Mendel
Mendel attributed his work to…
physics, laws, and grafting trees (precision of detail)
is a plant or animal that has reproductive organs normally associated with both male and female genders
Hermaphordite
Examples of hermaphrodites
snails and plants
Mendel studied what plant and why
Pea plants:
1. different varieties. with different characteristics
2. allowed easy crosses where parents can be controlled
Contain the pollen grains, where the male gametes are produced
anther
Pollen, produced by athers, floats to another plant or sticks to a ___
stigma (self-fertilize)
Provide food for the embryo
endosperm
How many sperms/nucleus are in the pollen tube
2
Pollen tube grows into a
micropyle
In fertilization of pollen with sperm, 1 sperm ___ and another sperm ___
fertilizes egg (zygote 2n)
fertilizes diploid (endosperm 3n)
Mendel carried out what two types of crosses?
Self fertilization (scissors)
cross fertilization (paint brush)
Pollen and egg are derived from dif plants in ___ to produce seeds
cross fertilization
The mating or crossing between two individuals that have different characteristics
hybridization
The offspring that result from such a mating
Hybrids
The morphological characteristics of an organism are termed
characteristics or traits
A variety that produces the same trait over several generations is termed a
true breeder
Example of a true breeder
only making dwarf plants
How many traits did Mendel study? Each trait showed how many variants?
7, 2
The seed color of a pea: green or yellow–What is mutant?
green
Mendel first crossed only two variants of 1 trait at a time: What kind of cross
Monohybrid
Even though a tall plant has TT, in a cross it only gives off…
One T
When Mendel crosses a tall and dwarf plant, F1 was ____. The F1 generation then self fertilizes to produce F2 generation. The ratio of this was __.
Tt (tall), 3:1
From Mendels monohybrid cross, he concluded that…
2 copies of inheritance and every plant has 2 copies
The two copies of a gene segregate (or separate) from each other during transmission from parent to offspring
Mendel’s law of segregation
The two hereditary factors a pea plant contains from each parent may be the same or different. If different, one is ___ and the other is ___
dominant and recessive
During gamete (sperm and egg) formation, the paired factors segregate ____
Randomly
Mendels results of 3:1 ratio of the two parental traits refuted what theory? Suggested what theory instead?
refuted a blending mechanism of heredity; particulate theory of inheritance
Completely Defective copies of genes are called…
“loss of function alleles”
Mendel’s ‘factors’ are now called
genes
different versions of the same gene
Alleles
An individual with two identical alleles of a gene is termed…
An individual with two different alleles of a gene, is termed
homozygous
heterozygous
refers to the specific allelic composition of an individual
Genotype
refers to the outward appearance of an individual
Phenotype
an intact fully functional copy/allele/version of a gene
Wild Type allele
a totally non-functional allele
Null allele
enables one to predict the outcome of simple genetic crosses
Punnett square
Crossing individual plants that differ in two traits
Dihybrid Cross
Mendel reasoned that seed texture and color could either come from
the same inheritance particle or from separate inheritance particles
In a dihybrid cross, what is the ratio
9:3:3:1
The traits of color and smoothness arrived from
different inheritance factors or genes
During gamete formation, the segregation of any pair of hereditary determinants is ___ of the segregation of other pairs because ___
independent, on different chromosomes
The accuracy of the probability prediction depends largely on the
size of the sample
Random sampling error is large for ___ and small for ___
small samples, large samples
The probability that one OR the other of two mutually exclusive outcomes will occur is the sum of their respective probabilities
Sum Rule
Example of sum rule
You have a 14% chance of dying of cancer
You have a 17% chance of dying of heart disease
You, therefore, have a 14 + 17 = 31% chance of dying from cancer or heart disease
The probability of getting either one of two mutually exclusive events is the…
sum of the two probabilities
When rolling a dice, getting a 5 or a 2 are what kind of events
mutually exclusive events
the probability of rolling a “5” is 1/6
the probability of rolling a “2” is 1/6
The probability of rolling a 5 or a 2 is…
1/6 + 1/6 = 2/6 = 1/3
The probability an outcome involving one gene and another outcome involving another gene will occur at the same time is equal to the….
product of their respective probabilities
Ry vs. rY vs. ry vs. RY
Ry: round and green
rY: wrinkled and yellow
ry: green and wrinkled
RY: round and yellow
