MODULE 5. HEREDITY Flashcards

Question

definition - Gonadotropin-releasing hormone (GnRH)-

Answer 1

hormone released by the hypothalamus that regulates the production of follicle-stimulating hormone and luteinizing hormone from the pituitary gland

Answer 2

one set of chromosomes per cell (n) found in the sex cells (23 in humans)

Answer 3

possessing a pair of unlike alleles for a particular gene

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possessing a pair of identical alleles for a particular gene

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chromosomes that are similar in shape and form and the genes they consist of. One set comes from the father and the other from the mother.

Answer 6

The transmission of genetic information from a parent to a child

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The special cell division which only takes place in the sex cells of females and males, resulting in egg and sperm cells that contain 23 chromosomes (the haploid number). ‘Daughter’ cells not identical to parent cells.

Answer 8

approximately 28-day cycle of changes in the uterus consisting of a menses phase, a proliferative phase, and a secretory phase

Answer 9

The process of cell division in body cells. Mitosis results in 'daughter' cells which are genetically identical to the parent cells.

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- A permanent, heritable change in the base sequence in a gene or a chromosome;

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-cell that results from the division of the oogonium and undergoes meiosis I at the LH surge and meiosis II at fertilization to become a haploid ovum

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process by which oogonia divide by mitosis to primary oocytes, which undergo meiosis to produce the secondary oocyte and, upon fertilization, the ovum

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-approximately 28-day cycle of changes in the ovary consisting of a follicular phase and a luteal phase and a luteal phase

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-female gonads that produce oocytes and sex steroid hormones (notably estrogen and progesterone)

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-release of a secondary oocyte and associated granulosa cells from an ovary

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haploid female gamete resulting from completion of meiosis II at fertilization

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reproduction from an ovum without fertilization, especially as a normal process in some invertebrates and lower plants

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male organ of copulation

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the physcial or chemical expression of an organism's genes e.g. brown eyes

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definition - smaller cell produced during the process of meiosis in oogenesis

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-doughnut-shaped gland at the base of the bladder surrounding the urethra and contributing fluid to semen during ejaculation scrotum external pouch of skin and muscle that houses the testes

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an allele that is only expressed whn the organism is homozygous for that allele and not expressed when heterozygous (When paired with a dominant allele)

Answer 23

ejaculatory fluid composed of sperm and secretions from the seminal vesicles, prostate, and bulbourethral gland

Answer 24

gland that produces seminal fluid, which contributes to semen

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the intentional breeeding of organisms with desirable trait in an attempt to produce offspring with similar desirable characteristics or with improved traits

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tube structures within the testes where spermatogenesis occurs

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the production of new living organisms by combining genetic information from two individuals of different types (sexes)

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single nucleotide polymorphisms, frequently called SNPs are the most common type of genetic variation among people. each snp represents a difference in a single nucleotide

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also, spermatozoon) male gamete

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a reproductive cell capable of developing into a new individual without fusion with another reproductive cell. Spores are produced by bacteria, fungi, algae, and plants.

Answer 31

male gonads

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muscular hollow organ in which a fertilized egg develops into a fetus

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tunnel-like organ that provides access to the uterus for the insertion of semen and from the uterus

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diploid (2n) cell resulting from the union of two gametes in sexual reproduction

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- Gametes are produced by parent organisms through meiosis. - Each gamete contains half the necessary number of chromosomes - The male gamete (sperm) fertilises the female gamete (ovum or egg) by either internal fertilisation (mammals) or external fertilisation (fish such as salmon) - Fusion of gametes results in production of a zygote, which contains a combination of genetic material from parental organisms

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- Combination of chromosomes from two organisms INCREASES IN VARIATION, which assists with survival

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- Large number of gametes produced generally means more off spring. It is also a simpler behavioural process which does not require mating rituals

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- INCREASED LIKELIHOOD OF FERTILISATION as egg and sperm are in close proximity, with INCREASED PROTECTION from the environment leading to higher survival rates of offspring.

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- Requires mating of two organisms which is dependent on syncing fertility cycles, and the production of offspring is lower and less prolific than asexual reproduction

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- Species must produce larger numbers of gametes, which requires extra energy. It also requires a watery environment (may be difficult for amphibians )

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- Fewer offspring are produced, and it is more difficult to bring males and females into contact. There is higher risk of sexually transmitted infections passing between organisms.

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involves the fusion of gametes outside of the body.

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involves the fusion of gametes inside of the body of a parent

Answer 44

Flowers are the reproductive organs in plants. Male parts  the filament and the anther (together called stamens). Anthers produce pollen which contains sperm cells of a plant. Female parts  the female part (carpel) consists of the stigma, style, ovary and ovule.

Answer 45

Creates genetic diversity within a species, leading to higher levels of disease resistance and a greater ability to adapt to changing conditions.

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Can prevent favourable genes from being passed to offspring (if it’s a recessive gene), which is not possible for an isolated organism

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- the stem from the plant is cult and is planted in the soil that will gradually grows and turn into another plant.

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E.G. roses

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stems extending from the plant and along the soil

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strawberry

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 Bulbs are underground food stored organs that can grow and develop into new plants

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Offspring are clones parent plants, meaning favourable traits are effectively passed through generations. This is advantageous for farmers or ensure consistency in their crops. It is less energy intensive than sexual reproduction, meaning the population can increase rapidly and exploit suitable habitats quickly

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Pathogens may spread easily from parent to offspring. This reduction in genetic diversity increases the susceptibility of species to new diseases, and evolution is reduced due to the lack of genetic variation.

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Budding in fungi such as yeast involves the parent cell developing a bud cells, a daughter nucleus. Overtime, this bus undergoes cell division (mitosis) while still being attached to the parent which may result in a chain of bud cells. The bus separates from its parent fungus when it grows to a sufficient size to be able to support itself independently. This now-separated bud undergoes further cell division to produce more bud cells. The result is genetically identical to the parent.

Answer 55

budding | spores

Answer 56

Spores in moulds and mushrooms are micro reproductive units that can be formed as a result of mitosis or meiosis. Spores differ from gametes as they do not need to combine with another spore to form offspring. Hyphae are fine, thread like structures that branch out and have ends that are capable of producing spores called sporangia. These asexual spores are carried by the wind, then germinate to form genetically identical new hyphae.

Answer 57

- Production of spores allows for offspring to be widely distributed in the environment, increasing colonisation. They can also be produced easily in large numbers

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binary fission

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- A single cell divides into two identical daughter cells - Begins with DNA replication where the genetic information of the bacteria is copied and divided in two. - The cell elongates and splits into two (cytokinesis) producing daughter cells with identical genomic information (i.e. clones of the parent).

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- Very rapid (e.g. E.coli can replicated as fast as every 20 mins in the right conditions, and only requires a single organism to order to produce offspring.

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- Lack of genetic diversity in the resulting population lowers chance of organism survival. However, this may be overcome by high rates of mutation dying DNA replication, and horizontal gene transfer (HGT) by plasmids, which can be passed from bacteria to bacteria

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binary fission | budding

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- Variation in the population - Species better able to adapt to their environments - Disease events less likely to affect entire population

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- Large time and energy investment - Requires a mating partner - Fewer offspring produced

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The fertilisation process occurs in one of the fallopian tubes in the humans body. The sperm enters the vagina, travels up through the uterus and then along one of the fallopian tubes where it can combine and fertilise the mature egg.

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1ST TRIMESTER  high levels of progesterone also stimulate changes in the mothers body. These changes include enlargement of the uterus, formation of a mucous plug to seal the cervix, growth of the maternal parts of the placenta, and breast growth.

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2ND TRIMESTER  High levels of oestrogen and progesterone are vital to continue maintaining pregnancy. However, the production of embryonic HCG declines and the corpus luteum deteriorates, stopping it from producing these hormones. Instead, the placenta takes over the role of producing oestrogen and progesterone.

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3RD TRIMESTER  increased oestrogen is released, this oestrogen induces receptors to form on the uterus wall that can bind the hormone oxytocin. Oxytocin is critical to triggering and maintaining labour. An increased production of oxytocin occurs during labour.

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timing passing of favourable traits ensuring success pregnancy yields

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1. Detection of female cows in oestrus (animals in heat i.e. Sexually receptive) 2. Collection of semen (may be performed manually using an artificial vagina or by stimulation) 3. Insemination usally preformed using an insemination gun which shoots semen into the cervix of gthe desired animal

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CELL REPLICATION  The process by which cells replicate their genetic material and divide to form new cells.

Answer 72

Parent cell  DNA replicates  chromatin shortens and thickens to form chromosomes (prophase)  chromosomes line up individually (metaphase) spindle fibres attach to centromeres (anaphase) spindle fibres shorten, centromeres break and chromatids move apart (telophase) cytoplasm separates, cell and nuclear membrane form, chromosomes uncoil (cytokinesis) 2 identical daughter cells

Answer 73

Mitosis is important as it creates new body cells that are needed for growth, repair and maintenance. Important for the individual – to heal injuries, grow and survive Important for the species – increases an organism’s chances of reproducing

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Interphase – The parent cell grows and replicates its DNA Prophase 1. – DNA condenses into chromosome (between these steps crossing over occurs – link to genetic variation – recombination of DNA) Metaphase 1. - The parent cells nuclear membrane breaks down and the chromosomes move to the equator of the cell. (random segregation of chromosomes – many different combinations of maternal and paternal chromosomes moving to the poles – link to genetic variation) Anaphase 1. – A network of spindle fibres separates them to opposite poles of the cell Telophase 1. - nuclear membranes reform around the separated chromosomes and the cell membrane pinches off to make two daughter cells (cytokinesis) (another round of division) Prophase 2.- Nuclear membranes break down Metaphase 2. - the chromosomes align at the equator Anaphase 2. – the network of fibres separates the sister chromatids Telophase 2 and cytokinesis – nuclear membranes form at each end of the cells and the cell membranes pinch the cells in half

Answer 75

genetic variation

Answer 76

1. Unravelling the DNA 2. Building a new strand 3. Forming the DNA backbone

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UNRAVELLING THE DNA - The enzyme DNA helicase breaks the hydrogen bonds between the bases, ‘unzipping’ the double helix into single strands.

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BUILDING A NEW STRAND  “semi conservative” When DNA is produced, one of the strands in each new DNA molecule comes from the old DNA molecule. – reduces the chance of copying a strand incorrectly  DNA polymerase helps bind free nucleotides in the cell nucleus to the single strands – meaning an identical copy of the DNA strand is produced

Answer 79

FORMING THE DNA BACKBONE  DNA polymerase stitches these newly joined nucleotides together so that the sugar-phosphate back bone is formed.

Answer 80

in cytoplasm

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small and circular

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the order of amino acids

Answer 83

an mRNA copy of a gene is made and DNA is used as a template

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1. RNA polymerase attaches to DNA at the desired gene and separates the strands to expose the nucleotides in that region. (Only the section with the gene is pulled apart, not the whole DNA strand) 2. One strand is used as a template to make mRNA strand identical to the other strand, through complementary base pairings. (mRNA is made by complementary base pairing e.g. c with g) 3. Free floating nucleotides pair with their complementary bases on the template strand (RNA U replaces T) 4. The RNA polymerase reaches a stop codon and lets go of the DNA strand. (production is complete for prokaryotes) 5. In eukaryotes. Introns are spliced out of the strand and exons are stuck together to form the final mRNA strand. 6. mRNA molecules leave the nucleus and enter the cytoplasm through nuclear pore

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: mRNA is converted to a polypeptide chain. A polypeptide chain is formed according to the sequence of codons.

Answer 86

1. mRNA attaches to a ribosome at a particular start codon 2. The rRNA molecule with the correct anticodon pairs up with the mRNA in the ribosome. 3. A second tRNA molecule attaches to the next codon on the mRNA strand. 4. The ribosome catalyses the formation of a peptide bond between the two amino acids 5. The ribosome contains to move along the mRNA until it reaches a stop codon 6. The polypeptide chain and mRNA strand are released from the ribosome.

Answer 87

nucleus and cytoplasm

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carries info from DNA in the nucleus to the ribosomes

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At one end of the tRNA are three unpaired bases, called an anticodon, which attach the tRNA to its complementary bases (codon) on the mRNA strand. The other end of the tRNA is able to bind with amino acid temporally. Each tRNA molecule will only attach to one particular amino acid.

Answer 90

rRNA  forms a structural part of ribosomes and is made in the nucleolus

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Two dominant alleles result in a blended phenotype. E.G. a red flower x a white flower = heterozygous pink flower

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E.G. a red flower x a white flower = heterozygous pink flower

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= two dominant alleles result in both phenotypes being expressed at the same time.

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E.G. black chicken X white chicken = heterozygous having both black and white feathers

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when an allele is located on the X chromosome

Answer 96

. haemophilia or colour blindless. In order to have haemophilia you have to have two copies of the recessive allele.

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= occur with genes that have more than two alleles.

Answer 98

human blood

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how traits are passed on over many generations

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features that are controlled by multiple genes

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there are 2 main eye colours - but 14 other genes that play a role in determining a persons exact eye colour

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E.G. a person may have a genetic tendency to be underweight or obese, but his or her actual weight will depend on diet and exercise (these factors play a greater role than genes)

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by causing difference n the genes coding for specific proteins- these differences can influence a variety of traits e.g. appearance, disease susceptibility

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 Single nucleotide polymorphism (SNP) occurs where one nucleotide in the genome of an individual is different to the rest of the populations nucleotide at the same locus of the chromosome. This is because, due to SNP, a new nucleotide randomly replaces or substitutes an existing nucleotide in the organisms DNA sequence

Answer 105

Scientists have found that many biological questions can be answered using smaller regions of the genome that show polymorphisms. If there is crossing over during meiosis, the SNPs on a chromosome might not be all inherited together.

Answer 106

the sequence of nucleotides in DNA | AGTC

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sanger method | maxam-gilbert methods

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One of the methods that is able to determine the exact nucleotide sequence of a gene on a chromosome. A range of next-generation sequencing technologies are faster and more cost effective and can sequence many fragments at the same time.

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involving chemical reactions thta are specific tp the nucelotides

Answer 110

polymerase chian reaction - PCR is a process that is used to make millions of copies of a gene. This occurs outside the cell and involves amplifying specific DNA sequences by multiple cycles of replication, heating and cooling. The basic steps are: a. DENATURATION – (96 degrees) heat the reaction strongly to separate or denature the DNA strands. This provides single-stranded template for the next step b. ANNEALING – Cool the reaction so the priers can bind to their complementary sequences on the single-stranded template DNA c. EXTENSION – (72 degrees) Raise the reaction temperature so Taq polymerase extends the primers, synthezing new strands of DNA

Answer 111

a. DENATURATION – (96 degrees) heat the reaction strongly to separate or denature the DNA strands. This provides single-stranded template for the next step b. ANNEALING – Cool the reaction so the priers can bind to their complementary sequences on the single-stranded template DNA c. EXTENSION – (72 degrees) Raise the reaction temperature so Taq polymerase extends the primers, synthezing new strands of DNA

Answer 112

In genetic testing: it is essential in the identification of exact nucleotide sequence which allows scientists to determine if there is a mutation that is responsible for a disease as it is used to amplify genes associated with genetic disorders from the DNA of patients. E.G. 20 possible gene associated to late stage Alzheimer’s disease.

Answer 113

Using a process known as gel electrophoresis, scientists can place the DNA samples into an agarose gel and run an electric current through DNA samples.

Answer 114

DNA PROFILING, known as DNA finger print analysis, is a scientific technique used to identify and compare individuals by characteristics in their DNA.

Answer 115

Type of DNA that is used most in fingerprinting is STR. Scientists have found areas in human DNA that repeat the same sequences over and over but have different number of times.

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Useful for forensic investigations (identifying suspects or victims based on crime-scene DNA). It can be used to confirm if people are related to each other, such as for paternity testing. It can also be useful to confirm people are related to each other, e.g. paternity testing.

Answer 117

POPULATION GENETICS = a field of study which is used to investigate the differences within and between populations including the frequency of genes and alleles.

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Conversation genetics relies on gathering genetic data, for biodiversity conversation and to make informed decisions about protecting populations that are endangered or nearing extinction.

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to compare individual's in different populations in order to determine which population is more closely related to each other

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a diagrammatic representation of the genetic diversity within a group

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describes a disease that is controlled by a single gene

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– when individuals have different phenotypes, usually arising as a result of mutation; when are different forms of the same gene

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a branch of science that combines components of population genetics with historical, archaeological and linguistic evidence to determine the pathways of human evolution

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• aims to explain the causes of human diversity (mutations, natural selection, genetic drift, gene flow)

MODULE 5. HEREDITY Flashcards

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