Lecture 1

Question 1

pre-formationists

Answer 1

ovists (full-ass baby in the egg) vs. animaculists (full-ass baby in sperm)

One sex fully responsible for offspring. Founded by Von Leeuwenhoek in 18th century.

Question 2

blending inheritance

Answer 2

Inheritance in which no component is obtrusive– blending of characteristics from both egg and sperm. (19th century)

KEY COMPONENT– you can never produce an offspring with similar phenotypes to parents

Question 3

Law of Segregation

Answer 3

ONLY APPLIES TO ALLELIC STATE OF A SINGLE GENE

only one allele from each parent is assigned to the gamete

Question 4

Three Components of Mendel’s system

Answer 4

1) Homozygosity of alleles controlling phenotype of interest
2) Paternity must be controlled and known
3) All genotypes should be equally fertile

Question 5

gene

Answer 5

any sequence of nucleotides in a genome that encodes for a functional RNA

Question 6

gene locus

Answer 6

position of the nucleotides for a specific gene on a chromosome

Question 7

allele

Answer 7

one or more alternate forms of a gene that can exist at a single gene locus for a single gene

Question 8

dominant allele

Answer 8

expresses its phenotypic effect in a heterozygote

• A haploid organism only has one copy of every gene so it is neither homozygous or heterozygous.*
• An allele is neither dominant nor recessive if the heterozygote looks different from either homozygote.*

Question 9

wild-type

Answer 9

genotype or phenotype most commonly found in nature OR a lab

Question 10

Law of Independent Assortment

Answer 10

This law states that for each allelic pair of multiple genes (on separate chromosomes!!), segregation is independent for each gene during the formation of gametes.

i.e. One gene’s separation does not impact another one (they are not linked!!)

Question 11

Forward Genetics

Answer 11

Genes are first identified by mutant alleles and mutant phenotypes and later cloned and subjected to molecular analysis.

biological process -> mutant phenotype -> gene

Question 12

Reverse Genetics

Answer 12

Begins with cloned DNA segment or protein amino acid sequence and uses directed mutagenesis to introduce altered genes back into the genome to investigate function.

gene–>phenotype–>biological process

CRISPR

Question 13

Simple dominance

Answer 13

an allele is dominant if it has the same phenotypic effect in heterozygotes and homozygotes

Question 14

haplosufficient

Answer 14

in a diploid cell, an allele that can promote wild-type function with only one copy (common case)

+/a is sufficient to produce wild-type function

Question 15

haploinsufficient

Answer 15

in a diploid cell, an allele that cannot promote wild-type function with only one copy (rare)–often tied to dominant mutations

a null (amorphic) allele produces no normal RNA or protein product– can be deadly

Question 16

mutation

Answer 16

permanent change in DNA that makes up a gene

range in size from a single nucleotide to entire sets of chromosome

Question 17

De novo mutations

Answer 17

Not inherited mutations– occur just after fertilization, no family history

Can still get passed down because they occur only in an egg or sperm cell

Question 18

germline mutation

Answer 18

inherited and occur in testes and ovaries, will be passed on to children

All cells affected in offspring

Question 19

somatic mutation

Answer 19

occur in body cells– not inherited but could still affect the person during their lifetime

Cancer is a somatic mutation

Question 20

Chromosomal Theory of Inheritance

Answer 20

chromosomes are the vehicles of genetic heredity. Neither Mendelian genetics nor gene linkage is perfectly accurate; instead, chromosome behavior involves segregation, independent assortment, and occasionally, linkage.

Question 21

chromosome

Answer 21

typically, a linear double-stranded DNA molecule complexed with proteins that moves as an independent unit during mitosis and meiosis.

Question 22

sister chromatids

Answer 22

One of two visibly distinct, side-by-side and genetically identical copies of a replicated chromosome. Joined at their centromeres.

Question 23

centromere

Answer 23

A chromosomal locus that regulates chromosome movement during mitosis and meiosis. Sister chromatids are joined together by a common centromere.

Question 24

kinetichore

Answer 24

A specialized structure that forms at the centromere. It links chromatids to the spindle microtubules

Question 25

homologous chromosomes

Answer 25

• contain the same arrangement of genes
• identical in visible structure
• pair during meosis I
• In nature, not usually identical but typically exhibit allelic differences (maternal & paternal)
• CAN ALSO REFER TO– Chromosomes in different species that have retained most of the same genes during their evolution from a common ancestor*

Question 26

Theodor Boveri linked ____ and ______ for the first time.

Answer 26

chromosomes and heredity.

Saw segregation for the first time

Question 27

sex chromosome

Answer 27

presence or absence is correlated with the sex of the organism, plays role in sex determination

Question 28

autosome

Answer 28

any chromosome not a sex chromosome

Question 29

Trisomy X

Answer 29

XXX, does not seem to impact fertility

Question 30

Klinefelter

Answer 30

XXY, male

in humans, SRY gene determines male (on the Y chromosome)

Question 31

Turner

Answer 31

XO, female, no Y chromosome to hold the SRY gene

Question 32

In drosophila, the XO fly is a ____.

Answer 32

sterile male. In flies, Y chromosome is not involved in sex determination but it is required for male sexual function.

Question 33

hemizygous

Answer 33

biological sexes with 2 different chromosomes, ex. males are X,Y for humans

males more likely to show mutant phenotype

Question 34

nondisjunction

Answer 34

when homologous chromosomes fail to separate (or sister chromatids fail to separate in mitosis)