Inheritance Flashcards by Liam Bohan

Gregor _______ studied pea plants when studying heredity because they could produce _______, there are many variates, they are small and easy to grow, and can self-_______ or be cross-_______

Mendel, hybrids, fertilize, fertilized

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Mendel’s experimental method was in three stages: Produce _______-_______ strains for each trait he was studying; _______-_______ two of these strains having alternate forms of a trait (and perform _______ crosses); Allow the _______ offspring to _______-_______ for several generations

true-breeding, cross-fertilize, reciprocal, self-fertilize

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A _______ _______ is used to study only two variations of a single trait

Monohybrid cross

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Mendel produced true-breeding pea strains for _______ traits

seven

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The _______ generation is where offspring are produced by crossing two true-breeding strains

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Visible trait in the F1 generation was referred to as _______

dominant

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The alternative trait in the F1 generation was called _______

recessive

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In Mendel’s F1 generation with the pea plants, there were no plants with _______ characteristics of parents produced, meaning there was no _______ inheritance

intermediate, blending

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How is the F2 generation produced?

The self-fertilization of F1 plants

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Although masked in the F1 generation, the _______ trait reappeared among some F2 individuals

recessive

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Mendel found always about a _______:_______ ratio of dominant : recessive traits in the _______ generation

3:1, F2

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Mendel discovered that instead of 3:1 dominant : recessive in F2, the ratio is actually __ _______-_______ dominant : __ _______-_______-_______ dominant : __ _______-_______ recessive

1 true-breeding, 2 non-true-breeding, 1 true-breeding

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Mendel’s 5-element model:

Parents transmit discrete _______ (_______)
Each offspring individual receives what?
Not all copies of a gene are _______
Alleles remain _______ - no _______
Presence of _______ does not guarantee _______

factors (genes), one copy of a gene from each parent, identical, discrete, blending, allele, expression

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_______ - Alternative form of a gene

Allele

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_______ - two of the same allele

Homozygous

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_______ - different alleles

heterozygous

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_______ allele - expressed

Dominant

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_______ allele - hidden by dominant allele

Recessive

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_______ - Two alleles for a gene segregate during gamete formation (one from each parent) and are rejoined _______ _______ during fertilization

Segregation, at random

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A _______ _______ is used to study two variations of two traits in a single cross

Dihybrid cross

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The F1 generation of a dihybrid cross chows only the _______ _______ for each trait

dominant phenotypes

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A dihybrid cross produces what ratio?

9:3:3:1

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For the dihybrid cross Rr Yy x Rr Yy the 9:3:3:1 ratio would be (_______):(_______):(_______):(_______)

(R_ Y_):(R_ yy):(rr Y_):(rr yy) - where an underscore represents a dominant or recessive allele

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In a dihybrid cross, the alleles of each gene are _______ _______

independently assorted

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In a dihybrid cross, the _______ of different allele pairs is independent - for example seed shape is independent of seed color

segregation

The independent alignment of different homologous chromosome pairs during _______ _______ leads to the _______ _______ of the different allele pairs

metaphase I, independent segregation

A _______ is used to determine the genotype of an individual with an unknown phenotype

testcross

In a testcross you always cross the unknown genotype with what?

a homozygous recessive

_______ _______ _______: The probability that either of two mutually exclusive events occurs is the sum of their individual probabilities

Rule of addition

When crossing Pp x Pp, the probability of producing Pp offspring is what? Why

Probability of obtaining Pp (1/4) PLUS probability of obtaining pP (1/4) = 1/2

_______ _______ _______: Probability of two independent events both occurring is the product of their individual probabilities

Rule of multiplication

When crossing Pp x Pp, what is the probability of obtaining pp and why?

Probability of p from father: 1/2; probability of p from mother: 1/2; probability of pp = 1/2 x 1/2 = 1/4

_______ _______ refers to different phenotypes from the same genotype due to environmental conditions

phenotypic plasticity

_______ _______ refers to a range of possible phenotypes across genotypes

Continuous variation

Often a phenotype is the result of an accumulation of contributions by multiple _______, and these traits show continuous variation and are referred to as _______ _______

genes, quantitative traits

_______ _______ _______ (H^2) is the fraction of phenotypic variation due to underlying genetic variation

Broad sense heritability

_______ _______ _______ (h^2) is the fraction of phenotypic variation due to additive genetic variance

Narrow sense heritability

_______ refers to an allele hat has more than one effect on the phenotype

Pleiotropy

_______ _______ is where the heterozygote is intermediate in phenotype between the two homozygotes

Incomplete Dominance (like pink flowers)

_______ is where a heterozygote shows some aspect of the phenotypes of both homozygotes

Codominance (like type AB blood)

Human ABO blood demonstrates both _______ and _______ _______.

Codominance, multiple alleles

In human ABO blood, there are three alleles of the I gene (__, __, and __). The first two are _______ to the 3rd, but _______ to each other

I^A, I^B, i, dominant, codominant

_______ is when the action of one gene obscures the effects of another gene

Epistasis

When working with the fruit fly, T.H morgen discovered a _______ male fly with _______ eyes instead of red. He crossed this male fly with a normal red-eyed female

mutant, white

When Morgan crossed the mutant white-eyed fly with a normal red-eyed female, all of the F1 _______ had what?

progeny, red eyes (dominant trait)

When Morgan crossed the F1 females and F1 males, the F2 generation contained what?

Both red and and white-eyed flies, but all white-eyed flies were male

A _______ of an F1 female fly with a _______-_______ male showed the viability of _______-_______ females

testcross, white-eyed, white-eyed

Morgan concluded that the eye color gene resides on the _______ _______ _______

female X chromosome

Traits determined by sex chromosome genes are _______-_______

sex-linked

_______ _______ are a pair of dissimilar chromosomes that still pair during meiosis and mitosis

Sex chromosomes

Sex determination in Drosophila is based on the number of _______ _______

X chromosomes

_______ _______ varies across organisms: It is based on the presence of a Y chromosome in humans. In birds the male has two Z chromosomes and females are ZW.

Sex determination

Humans have _______ total chromosomes. 22 pairs are _______, and 1 pair are _______ _______

46, autosomes, sex chromosomes

In organisms with XY sex-determination, few genes from the __ chromosome are expressed.

Human males have __ chromosomes

Human females have __ chromosomes

Certain genetic diseases affect _______ to a greater degree than _______

males, females

_______ _______ ensures equal expression of genes from sex chromosomes even though the number of chromosomes is different between the sexes

Dosage compensation

In mammal female cells, 1 X chromosome is randomly inactivated and is highly condensed into a _______ _______

Barr body

Females heterozygous for genes on the X chromosome are _______ _______

genetic mosaics

Some exceptions to the chromosome theory: _______ and _______ contain genes and these don't follow the chromosomal theory of _______

Mitochondria, chloroplasts, inheritance

Genes from mitochondria and chloroplasts are often passed to the offspring by the mother, called _______ _______

maternal inheritance

_______ _______ exchanges alleles

Crossing over

If crossover occurs, parental alleles are recombined producing _______ gametes

recombinant

The result of the Creighton and McClintock experiment was that _______ recombinant progeny also have _______ recombinant chromosomes

genetically, physically

The conclusion of the Creighton and McClintock experiment was that a physical exchange of _______ _______ accompanied _______ _______

genetic material, genetic recombination

The distance between genes is proportional to the frequency of _______ events

recombination

recombination frequency = _______ _______ / _______ _______

recombinant progeny / total progeny

1% recombination = 1 _______ _______ = 1 _______

map unit (m. u.), centimorgan (cM)

Odd numbers of cross over events (1, 3, etc.) produce _______ _______, while no crossover or even numbers of crossovers (0, 2, etc.) produce _______ _______

recombinant gametes, parental gametes

_______ analysis is used to track inheritance patterns in families

Pedigree

_______ is the failure of homologues or sister chromatids to separate properly during meiosis

Nondisjunction

_______ is the gain or loss of a chromosome, and is the result of nondisjunction. _______ is the loss of a chromosome, and _______ is the gain

Aneuploidy, Monosomy, Trisomy

Autosomes __ and __ can survive to adulthood

21, 22

Trisomy __ (_______ _______) is where a human has a full 3rd chromosome

21, down syndrome

_______ of sex chromosomes can produce individuals with somewhat abnormal features, but often reach maturity.

Nondisjunction

Some examples of nondisjunction of sex chromosomes: XXX - triple-X females; XXY - males (_______ syndrome); XO - females (_______ syndrome); OY - _______ zygotes; XYY - males (_______ syndrome)

Klinefelter, Turners, nonviable, Jacob