Genetics

Question 2

What did Hippocrates say

Answer 2

males and females formed “pangenesis” in every organ – Move through their body through their blood to the genitals and then to their children

Question 3

Gregor Mendel

Answer 3

The father of modern genetics

Question 4

The human genome project

Answer 4

sequenced all of the DNA in a human cell

Question 5

Human karyotype

2 parts

Answer 5

• Of the 23 pairs of chromosomes, 22 are autosomes (found in both males and females)
• The other pair → sex chromosomes (Determine a person’s gender)

Question 6

Genes

Answer 6

Made up of a unique sequence of nucleotides + contains information needed to produce a specific protein

Question 7

Homologous chromosomes

Answer 7

Both carry genes controlling the same inherited characteristics at the same locus

Question 8

Alleles

Answer 8

Alleles are alternate forms of the gene that reside at the same gene loci on the pair of chromosomes
For each inherited characteristic, an organism has two alleles (one from each parent)

Question 9

If both alleles are the same

Answer 9

Homozygous (BB) or (bb)

Question 10

If both alleles are different

Answer 10

Heterozygous (Bb)

Question 11

Mendel’s hypotheses

4 parts

Answer 11

1. There are alternate forms of genes, which are the units that determine heritable traits, called alleles
2. For each inherited characteristic, an organism has two genes, one from each parent
3. When the two genes are different alleles and one: Is fully expressed → Dominant allele
   Has no noticeable effect on the organism’s appearance → Recessive allele
4. A sperm or egg carries only one allele for each inherited trait because alleles separate (segregate) from each other during production of gametes

Question 12

P generation

Answer 12

True breeding parents: PP and WW

Question 12

what did mendel do when he wanted cross-fertilization

Answer 12

cut the stamens from an immature flower to prevent self-fertilization + dusted the pistil from another plan on this female

Question 13

Offspring of two different varieties

Answer 13

hybrids

Question 14

Cross-fertilization

Answer 14

hybridization

Question 15

Genotype

Answer 15

genetic makeup of the organism

Question 16

Phenotype

Answer 16

expressed trait of an individual

Question 17

Rules of probability and inheritance

Answer 17

Probability of a compound event is the product of separate probabilities of the independent events

Question 18

why are dominant dissorders rare

Answer 18

Lethal dominant genes are always expressed + result in death so Deadly genes aren’t passed on to the next generation

Question 18

why are recessive diseases more frequent

Answer 18

People who carry a single recessive allele don’t express it, but can pass the disease → carriers

Question 18

The testcross

Answer 18

Used to test whether an organism with a dominant phenotype is homozygous or heterozygous

Question 19

Monohybrid crosses

Answer 19

focusing on ONE trait

Question 20

Dihybrid crosses

Answer 20

focusing on TWO traits

Question 21

The law of independent assortment

Answer 21

(Dihybrid crosses - two separate genes)
Each chromosome is inherited independently of the other chromosomes following the law of independent assortment

Question 21

The law of segregation

Answer 21

(Monohybrid crosses - dominant/recessive alleles)
During gamete formation, the two alleles separate as the homologous chromosomes move towards opposite ends of the cell during meiosis

Question 22

Pedigree analysis - when do you use

Answer 22

In situations where you don’t have the opportunity to perform controlled crosses

Question 23

spectrum of dominance

(3)

Answer 23

1. Complete dominance
2. Incomplete dominance
3. Codominance

Question 24

Complete dominance

Answer 24

In Mendelian genetics, one allele exhibits complete dominance over another

Question 25

Incomplete dominance

Answer 25

A cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blending of the parent traits

Question 26

Codominance

Answer 26

Heterozygous simultaneously express phenotype of both homozygotes

Question 27

Any gene located on a sex chromosome = ________

Answer 27

Any gene located on a sex chromosome = sex-linked gene

Question 28

facts about sex linked genes

(2)

Answer 28

1. Unrelated to sex determination
2. Are most often found on the X chromosome (longer+carries mroe genes)

Question 29

why are phenotypic expression more common in males

Answer 29

Because males have only a single X chromosome, functional variants cannot be “masked” by a second X chromosome.

Question 30

Recessive sex-linked traits are expressed much more frequently in ____ than _____

Answer 30

Recessive sex-linked traits are expressed much more frequently in males than females

Question 31

X inactivation in females

Answer 31

One x chromosome in each cell becomes inactivated during early embryonic development - Barr body

Question 32

Epistasis

Answer 32

the phenotypic expression of a gene at one locus alters that of a gene at a second locus

Question 33

Pleiotropy

Answer 33

A single gene may
affect multiple phenotypes

Question 34

Polygenic inheritance

Answer 34

characteristics that characteristics vary in a population along a continuum

Question 35

Phenotypes = __________ + __________

nature + nurture

Answer 35

Phenotypes = Genotype + Environment

Question 36

Genes set the limit for the phenotype, and the environment molds the phenotype _________

Answer 36

Genes set the limit for the phenotype, and the environment molds the phenotype within its limits