Patterns of Inheritance Flashcards

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1
Q

continuous variation

A

variation that produces phenotypic variation where the quantitative traits vary be very small amounts between one group and the next

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2
Q

discontinuous variation

A

genetic variation producing discrete phenotypes- 2 or more non-overlapping categories

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3
Q

quantitative genetics

A

the study of genetics of such inherited characteristics

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4
Q

directional selection

A

type of natural selection that occurs when an environmental change favours a new phenotype and so results in a change in pop mean

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5
Q

founder effect

A

when a small sample of an original population establishes in a new area and gene pool is not diverse

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6
Q

genetic bottleneck

A

sharp reduction in size of population due to environmental disasters which reduced genetic diversity and as pop expands, gets less diverse

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7
Q

stabilising selection

A

natural selection leading to constancy within a population, extreme phenotypes are selected against so removed from population, reduces genetic diversity

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8
Q

allele frequencies

A

the number of alleles at a particular locus of a population

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9
Q

artificial selection

A

selective breeding of organisms involving humans choosing desired phenotypes and interbreeding those phenotypes individually

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10
Q

inbreeding depression

A

during stages of selective breeding when individuals with desired characteristics/few undesired are bred, reducing genetic diversity in the gene pool and increasing the chance of inheriting 2 copies of recessive harmful alleles

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11
Q

hybrid vigour

A

when breeders outcross individuals belonging to 2 different varieties to obtain individuals that are heterozygous at many gene loci

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12
Q

examples of gene banks

A

rare breed farms, botanic gardens/zoos, seed banks, sperm banks, frozen embryos etc

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13
Q

selective breeding in livestock

A

IVF, artificial insemination, embryo cloning, embryo transplantation

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14
Q

selective breeding in plants

A

tissue culture, asexual reproduction

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15
Q

why did mendel study pea plants

A

easy to grow, naturally self-fertilising so easy to cross artificially

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16
Q

traits mendel compared in pea plants

A

stem height, seed shape, seed colour, pod shape, pod colour, flower arrangement, flower colour

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17
Q

heterozygous

A

not true-breeding so have different alleles at a gene locus on a pair of homologous chromosomes

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18
Q

homozygous

A

true breeding so have identical alleles at a gene locus

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19
Q

monogenic

A

determined by a single gene

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20
Q

dihybrid

A

involving two gene loci

21
Q

codominance

A

where both alleles present in the genotype of a heterozygous individual contribute to the phenotype

22
Q

multiple alleles

A

characteristic for which there are 3 or more alleles in the populations gene pool

23
Q

allopatric speciation

A

formation of two different species from one original species due to geographical isolation

24
Q

speciation

A

the splitting of genetically similar population into 2 or more populations that undergo genetic differentiation and reproductive isolation, leading to isolation of 2 or more species

25
Q

sympatric speciation

A

formation of 2 diff species from one original species, due to reproductive isolation while the populations inhabit the same location

26
Q

population

A

members of a species, living in the same place and at the same time, that can interbreed

27
Q

persistent mutation

A

transmitted through many generations without change

28
Q

random mutation

A

not directed by need on the part of the organism

29
Q

deletion

A

part of a chromosome lost

30
Q

inversion

A

section of a chromosome breaks off, turns 180’ so genes may be too far form their regulatory nucleotide sequences to be expressed

31
Q

translocation

A

piece of one chromosome breaks off and becomes attached to another, may interfere with regulation of genes

32
Q

duplication

A

piece of chromosome duplicated, too many certain proteins may disrupt metabolism

33
Q

non-disjunction

A

one pair of chromosomes fail to separate, leaving one gamete with an extra chromosome e.g. down syndrome

34
Q

aneuploidy

A

chromosome number is not an exact multiple of the haploid number so chromatids fail to separate

35
Q

polyploidy

A

if a diploid gamete is fertilised by a haploid gamete, resulting zygote will be triploid e.g. lumpy strawberry

36
Q

sex-linked

A

gene present on (one of) the sex chromosomes

37
Q

gene-linked

A

gene on the same chromosome (linkage group)

38
Q

factor 8

A

one of the genes on non-homologous region of X chromosome which codes for a blood-clotting protein (mutated form in sufferers of haemophilia A)

39
Q

codominant

A

where both alleles present in the genotype of a heterozygous individual contribute to the individuals phenotype

40
Q

autosomal linkage

A

gene loci present on the same autosome (non-sex chromosome) that are often inherited together

41
Q

linked

A

when two or more gene loci are on the same chromosome

42
Q

epistasis

A

interaction of non-linked gene loci where one masks the expression of the other

43
Q

hypostatic

A

when the alleles at the first locus are epistatic to those at the second locus so they are also epistatic to the first locus

44
Q

how is epistasis often explained

A

how the genes work to code for two enzymes that work in succession, catalysing sequential steps of a metabolic pathway

45
Q

calculated value of chi-squared is not significant when

A

it is larger than the critical value at p=0.05 so we accept the null hypothesis

46
Q

gene locus

A

the position of an allele on the chromosome

47
Q

genotype

A

the combination of alleles possessed by an organism

48
Q

allele

A

an alternative version of a gene

49
Q

recessive

A

allele only expressed when homozygous / in absence of dominant allele