Biology subjects

Makarewicz, C. A.

Publications and source records attributed to Makarewicz, C. A..

3 recordsLinked to original sources

bioRxiv2026

3,500 years of sheeppox virus evolution inferred from archaeological and codicological genomes

Sheeppox virus (SPPV) is a major livestock pathogen causing economic hardship through reduced production and death of vulnerable sheep, with written descriptions of sheeppox-like disease recorded since antiquity. We report 21 novel ancient SPPV genomes spanning the Eurasian steppe Bronze Age ([~]1,700 BCE) to the Early Modern period in Western Europe, including multiple genomes obtained from medieval parchment. We estimate that major capripoxvirus lineages diverged [~]11,500-3,700 years ago, overlapping known translocations and bio-cultural developments in sheep. Our dataset supports SPPV diverging first within the lineage leading to goatpox virus and lumpy skin disease virus, and that known gene inactivation events within SPPV and goatpox virus occur in our earliest SPPV genomes. These findings reveal that the food security of Eurasian communities have been threatened by sheeppox for over 3,700 years, and provide new insights to the genomic evolution and potential host adaptation of sheeppox virus. TeaserAncient viral genomes from manuscripts and teeth illuminate the evolutionary history of sheeppox virus.

genetics↗

bioRxiv2024

Developmental plasticity and genetic selection shaped cereal evolution in the Early Holocene southern Levant

The domestication of plants in southwest Asia was an evolutionary process that took place over several millennia in the Early Holocene. During this time domestic species developed distinct traits that distinguish them from their wild counterparts. Current models of plant domestication emphasise the role of genetic selection in the evolution of these traits, viewing these as heritable adaptations that arose in response to selective pressures associated with human cultivation. In cereals, domestication resulted in the evolution of non-shattering rachis and increased grain size, two traits that can be tracked directly in the archaeobotanical record. Measurements of cereal grains from Early Neolithic sites indicate that grain size increase occurred prior to the evolution of non-shattering rachis, and it has been proposed that this reflects selection for larger grains under tillage, signifying pre-domestication cultivation. Here we combine morphological and metrical analysis of cereal remains, stable carbon isotope analysis, and weed ecology to test this hypothesis, using three assemblages from the southern Levant: Pre-Pottery Neolithic A Sharara (c. 9250-9200 cal BCE), Pre-Pottery Neolithic A el-Hemmeh (c. 9400-8700 cal BCE) and Late Pre-Pottery Neolithic B el-Hemmeh (c. 7500-7000 cal BCE). Our findings indicate that increased grain size in the Early Holocene is better understood as a plastic response to variation in growing conditions (specifically moisture), rather than a result of genetic selection for increased grain size under cultivation (i.e., tillage). We argue that cereal evolution in southwest Asia was initially driven by developmental plasticity, followed by genetic selection. Significance StatementCereals were amongst the earliest crops domesticated in southwest Asia and remain central to modern agriculture. We can track cereal domestication archaeologically using a suite of morphological traits, which distinguish domestic species from their wild counterparts. The process by which these traits evolved is still not fully understood but has widely been framed as genetic adaptation to cultivation. Here we seek to disentangle how two key domestication traits relating to seed dispersal and size evolved. By taking a multi-stranded approach to new archaeobotanical evidence, we demonstrate that in the Early Holocene southern Levant, cereal domestication occurred in a sequence where developmental plasticity preceded genetic selection.

plant biology↗

bioRxiv2024

Differences in isotopic compositions of individual grains and aggregated seed samples affect interpretation of ancient plant cultivation practices

The stable carbon ({delta}13C) and nitrogen ({delta}15N) isotope analysis of charred archaeological grains provides a remarkably precise scale of information: the growing conditions under which a plant was cultivated in a single field and season. Here we investigate how the measurement of single individual grains or aggregate bulk samples for carbon and nitrogen isotopes impacts how we characterize variation and, consequently, our interpretations of ancient cultivation practices. Using experimentally grown barley (Hordeum vulgare var. nudum), this work investigates {delta}13C and {delta}15N intra-panicle variation between both uncharred and charred individual grains from four plants. We found limited intra- and inter-panicle isotopic variation in single grain isotope values, ca. 0.5{per thousand} in {delta}13C and ca. 1{per thousand} in {delta}15N, reemphasizing the degree to which grains are representative of their local growing conditions. To explore the interpretive impact of aggregate versus single-grain isotopic sampling, we measured charred barley recovered from a single storage context excavated from Trench 42 (ca. 1900 BCE) at Harappa. Aggregate samples of a random selection of Trench 42 barley demonstrated remarkable inter-sample homogeneity, with a less than 0.5{per thousand} difference in {delta}13C and {delta}15N values, reinforcing the ability of aggregate samples to capture a representative isotopic average of a single depositional context. However, the measurement of single-grains revealed moderate 2-3{per thousand} variation in {delta}13C, and an outstandingly wide isotopic variation of ca. 8{per thousand} in {delta}15N values, indicating the degree to which cultivation practices varied beyond what the bulk samples indicated. These results highlight how decisions in the selection and measurement of archaeological grains for isotopic analysis impact data resolution, with profound consequences for understanding past agricultural diversity.

plant biology↗